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Explained: 350 vs 1,100, CPCB vs IQAir, Who Has Got Delhi's AQI Right

Delhi's sky turned grey and hazy a day after Diwali fireworks lit up the city. The air, toxic, making the national capital the "most polluted major global city". The pollution levels or the Air Quality Index (AQI) soared to severe levels, resulting in difficulty in breathing, itchy eyes and causing discomfort to even healthy people. IQAir, a Swiss air-quality monitoring company, clocked the city's AQI at a staggering 1,121 on Tuesday. However, India's Central Pollution Control Board (CPCB) reported a much lower AQI of 351, falling under the "very poor" category. The catch is - both the readings are correct but for different reasons. What Is AQI? The Air Quality Index (AQI) is a public health tool designed to communicate air pollution levels or the quality of air in simple terms. Eight pollutants namely particulate matter (PM) 10, PM2.5, Ozone (O3), Sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), lead (Pb) and ammonia (NH3) act as major parameters in deriving the AQI of an area, as per the CPCB. "AQI is a calculated index based on different parameters. It is for common man's understanding of the quality of air," explained Mohan George, Consultant at the Centre for Science and Environment. "AQI has different color-coded ranges simply to tell the citizens that air is good or satisfactory or very poor and what they should be doing," George, also former Additional Director at Delhi Pollution Control Committee, added. For example, AQI between 401 and 500 or in the severe category is hazardous for even healthy people, and one should avoid going out or exercising in the open.

As Punjab gets attention, data suggests Haryana, UP contribute to over a third of Delhi’s PM 2.5

Punjab takes the heat for Delhi’s foul air. But the headlines often miss Haryana and Uttar Pradesh, which contribute significantly to the toxic mix. A total of 19 cities in the National Capital Region appear to have contributed to more than one-third of the PM 2.5 load in Delhi, suggests Newslaundry’s analysis of two weeks’ data compiled by an institute under the Ministry of Earth Sciences. Of these, 11 cities are in Haryana, six in Uttar Pradesh and two in Rajasthan. Newslaundry’s analysis from October 5 to 19 is based on regional and sectoral contributors forecast by Indian Institute of Tropical Meteorology (IITM), Pune under MoES. This data was analysed before the peak observed on Diwali. Data suggests that the contribution of local factors such as transport, industry, energy, waste burning etc was 35.4 percent between October 5 and 19. Among these, the share of the transport sector was the highest at 18.32 percent. The third highest contributor was a curious sector called “others” at 27.65 percent. It’s not clear what emission sources are included in the “others” category. Since 2021, IITM-Pune has been predicting PM2.5 load of Delhi with the help of the Decision Support System. It also releases air quality index forecast through the Air Quality Early Warning System (AQEWS), which enables the Commission for Air Quality Management to take pre-emptive measures. Based on mathematical modeling, DSS estimates the contribution of emissions from local sectors in Delhi, 19 districts in three neighbouring states, and biomass burning. The 19 cities contributing to Delhi’s air pollution are part of the National Capital Region, a vast metropolitan area comprising Delhi and several adjoining districts across Haryana, Uttar Pradesh, and Rajasthan. Given the transboundary nature of air pollution, these cities are integral to regional anti-pollution initiatives and plans such as the Graded Response Action Plan (GRAP) and other Commission for Air Quality Management (CAQM)-led measures. Regional contributors In the period analysed, 19 cities contributed 34.52 percent to Delhi’s PM 2.5 load, including 11 in Haryana. Among the three neighbouring states, Haryana’s average predicted PM 2.5 load to Delhi was the highest at 24.7 percent. The Haryana cities analysed by DSS are Karnal, Faridabad, Mahendargarh, Jhajjar, Rohtak, Sonipat, Panipat, Gurgaon, Rewari, Bhiwani and Jind. Among them, Sonipat’s average share was the highest at 5.71 percent, followed by Jhajjar at 5.62 percent. For two days (October 5 and 13), Jhajjar was responsible for almost one-tenth of Delhi’s PM 2.5 load. Sonipat saw its highest contribution on October 11 and 12 when its share was 11 percent and 9.3 percent, respectively. Experts attributed Haryana’s contribution to winds carrying pollutants flowing from its cities towards Delhi. Anumita Roy Chowdhury, executive director at Centre for Science and Environment, said: “The transboundary flow of pollution is determined by the direction of the wind. Delhi is on the downwind side of Haryana.” Referring to a source-apportionment study, she said Delhi’s contribution to Noida’s pollution can go up to 40 percent because the wind flow is from Delhi to Noida. On Jhajjar and Sonipat being the key contributors, she said they have industrial areas and thermal power plants. Uttar Pradesh’s average contribution in the two-week period was 8.4 percent with Gautam Buddh Nagar’s share at 3.05 percent and Ghaziabad at 2.53 percent. The other four districts part of DSS predictions are Meerut, Bulandshahr, Baghpat and Muzaffarnagar. The share of Rajasthan, which has Alwar and Bharatpur among the 19 cities, was the lowest at 1.39 percent.

350 or Over 1,000? Decoding Delhi’s Post-Diwali Air Quality Index

New Delhi: Delhi’s air quality plunged sharply a day after Diwali, leaving the city shrouded in haze and making it one of the world’s most polluted major cities. Residents reported difficulty in breathing, itchy eyes, and general discomfort. While Swiss-based air-quality platform IQAir recorded the city’s AQI at a staggering 1,121, India’s Central Pollution Control Board (CPCB) reported a much lower figure of 351. Both readings, however, are correct within their respective frameworks. Understanding AQI The Air Quality Index (AQI) is a tool designed to communicate air pollution levels in simple terms, helping the public understand associated health risks. CPCB calculates AQI based on eight pollutants: PM10, PM2.5, ozone (O3), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), lead (Pb), and ammonia (NH3). Mohan George, consultant at the Centre for Science and Environment, explains, “AQI uses color-coded ranges to indicate whether the air is good, satisfactory, or very poor, guiding citizens on necessary precautions.” For instance, an AQI above 400 falls in the “severe” category, hazardous even for healthy individuals. CPCB vs IQAir The key difference lies in methodology and scale. CPCB’s AQI scale is capped at 500, with six categories ranging from ‘good’ (0-50) to ‘severe’ (401-500). IQAir, however, has a tighter scale, labeling anything above 301 as “hazardous.” Both platforms identify the dominant pollutant usually PM2.5 in Northern India during winter but their calculation methods differ, leading to varying AQI values. Data Sources and Calculation CPCB relies on government-operated, reference-grade monitoring stations, including DPCC, IMD, and IIT Madras. IQAir incorporates data from these stations as well as additional sensor-based monitors from embassies, companies, and individuals. For example, if PM2.5 concentration reaches 1,100 micrograms per cubic meter, IQAir could report an AQI of 2,043, while CPCB’s calculation would show 1,054. Which Reading to Trust? Experts recommend focusing on the AQI category—“very poor,” “severe,” or “hazardous”—and pollutant concentrations rather than the numeric value alone. For instance, on Tuesday morning, IQAir recorded PM2.5 at 320 µg/m³ near Mandir Marg (AQI 489), while CPCB measured 335 µg/m³. Both indicate dangerously polluted air, underlining the need for precautionary measures such as limiting outdoor exposure and using masks or air purifiers. In essence, whether 350 or 1,100, the takeaway remains the same: Delhi’s air quality is hazardous, and public health measures are essential.

As pollution soared on Diwali night, Delhi’s air monitors fail at key moments

As Delhi’s skyline lit up unabated on Diwali night, the levels of pollutants skyrocketed far beyond permissible limits across the city. But at the very moment when tracking dangerous pollution peaks was most critical, the majority of Delhi’s 39 continuous ambient air quality monitoring stations (CAAQMS) went offline for hours, creating significant data gaps. An analysis of Central Pollution Control Board (CPCB) and Delhi Pollution Control Committee (DPCC) data by HT revealed that only nine stations – barely 23% of the city’s monitoring network – recorded continuous data. The remaining stations experienced blackouts ranging from one to nine hours during the crucial 36-hour period between midnight on Monday and 11am Tuesday. Dwarka Sector 8 recorded the poorest performance, with data available for only 27 of the 36 critical hours. Monitoring stations at Jawaharlal Nehru Stadium, Nehru Nagar, Patparganj, and RK Puram each lost approximately eight hours of readings. Four other stations missed only one hour, but 10 crucial monitoring points went dark for six hours or more during the period when firecracker emissions typically peak and accumulate. Data gaps and pollution spikes Experts stressed that the missing data is not a new phenomenon. Every year, several stations stop reporting when pollution levels spike during Diwali, suggesting the system’s inability to handle pollution loads beyond a certain threshold. “The observed pattern shows that most stations stopped providing data when they approached 1,000 µg/m³, while there were stations such as Anand Vihar, Nehru Nagar, Mundka, that recorded values above 1,000 µg/m³, indicating that the technology of monitoring isn’t an issue, at least in terms of being available. We have observed this over the past years too,” said Sunil Dahiya, founder and lead analyst of think tank EnviroCatalysts. Dahiya said the problem cuts across agencies. He referred to previous years, which had similar data gaps observed not only for stations under the Delhi Pollution Control Committee (DPCC), but also those under the Indian Institute of Tropical Meteorology (IITM), the Central Pollution Control Board (CPCB) and the India Meteorological Department (IMD). “This isn’t data being withheld. It is a technological limitation in the sense some stations are not able to record complete and accurate data beyond a certain limit,” Dahiya said, calling for stations to be suitably upgraded. Where data was available, the picture was alarming. DPCC’s Mandir Marg station recorded PM2.5 concentrations of 1,066 µg/m³ at midnight before going offline from 1am to 4am. At Nehru Nagar – Delhi’s most polluted station on Diwali night – PM2.5 touched 1,763 µg/m³ at 10pm, with no data for the next hour and a four-hour blackout between 1am and 5am. CPCB’s ITO station registered PM2.5 levels of 923 µg/m³ at 1am and went dark. It worked again at 7am when it logged 967 µg/m³. At Dwarka’s NSIT station, data vanished from midnight to 5am, while readings at IMD’s Ayanagar were unavailable for up to five hours. An expert, well acquainted with the CAAQMS across NCR, said for hourly readings – stations spend close to 40 minutes to collect particulate matter, with the remaining time spent to calibrate and analyse it. “Stations are designed to record extremely high values – even up to 10,000µg/m³. With the rise in concentration, accuracy may reduce but it does not mean values are not released. It simply means the accuracy is reduced marginally – by 1% or 2%. In this case, it is plausible a certain threshold has been set beyond which values will not be captured,” The cost of missing data These gaps, experts warned, undermine public health response and scientific understanding of pollution’s real impact. “Such missing data hampers insights, makes it impossible to assess exposure accurately, and gives a false sense that air quality is slightly better than it actually is,” said Dahiya. Activist Bhavreen Kandhari called it a “worrying breach of transparency.” “Reliable, continuous monitoring is the foundation of any clean-air strategy. Transparency in air quality data should be treated as a public health imperative, not a discretionary choice,” she said. Anumita Roychowdhury, executive director for research and advocacy at the Centre for Science and Environment (CSE), said such lapses were particularly concerning during “extreme pollution episodes” like Diwali. “High pollution peaks are expected during such extreme pollution episodes. It is thus highly important to keep the data open and transparent even if extreme peaks are recorded, to understand the magnitude of the impacts and to inform policy and people for adequate and effective health safeguards,” she said.

Delhi’s air quality worsens post-Diwali:Toxic haze and firecracker emissions weaken immunity, raising experts’ concerns over higher risk of viral infections and respiratory illnesses

Stubble burning has reduced, but it’s no longer the main culprit. What we’re seeing is a city choking itself with its own emissions,” said environmentalist Sunita Narain. “The solution lies in year-round enforcement, not just post-festival firefighting.” A thick layer of toxic haze enveloped Delhi for the second straight day after Diwali celebrations, as widespread violations of the Supreme Court’s two-hour green cracker window pushed the city’s air quality into the ‘very poor’ zone. According to data from the Central Pollution Control Board (CPCB), Delhi’s average Air Quality Index (AQI) stood at 345 at 7 a.m., with pollution levels in several parts of the capital hovering on the brink of the ‘severe’ category. Of the 38 CPCB monitoring stations, 34 recorded AQI readings between ‘very poor’ and ‘severe’, while Punjabi Bagh (433) and Wazirpur (401) were identified as pollution hotspots. Experts say calm winds, low temperatures, and stagnant weather conditions have worsened the haze, trapping pollutants close to the surface and delaying dispersion. Although farm fires across Punjab and Haryana reportedly fell by nearly 77% compared to previous years, the spike in pollution this year has been largely attributed to firecracker emissions and local sources such as vehicular exhaust, construction dust, and diesel generators. The post-Diwali PM2.5 average shot up to around 488 micrograms per cubic metre, more than double the pre-festival levels, according to a Climate Trends analysis. Health concerns mount amid deteriorating air Doctors have raised alarms over the health impact of prolonged exposure to toxic air, warning that it not only irritates the lungs but also weakens the body’s natural immune defenses.“High levels of air pollution alter the immune response in the respiratory tract by reducing the activity of macrophages and natural killer cells the body’s frontline soldiers against infections,” explained Dr. Randeep Guleria, former AIIMS Director. “This makes individuals more susceptible to viral illnesses such as influenza and COVID-19.” Studies have shown that pollutants like PM2.5 can damage the cilia in the respiratory tract, disrupt airway barriers, and trigger chronic inflammation creating a favourable environment for viruses to thrive. The combination of cooler post-monsoon temperatures and reduced humidity further aids viral survival and transmission. Health experts have advised citizens, especially children, the elderly, and those with respiratory ailments, to avoid early-morning walks, wear N95 masks outdoors, and use air purifiers indoors. Authorities activate GRAP Stage II Measures With pollution levels escalating, the Commission for Air Quality Management (CAQM) has enforced Stage II of the Graded Response Action Plan (GRAP), which includes restrictions on construction activities, a ban on diesel generator use (except for essential services), and advisories to curb vehicular pollution. Meanwhile, political sparring has erupted between the AAP and BJP over the failure to prevent firecracker violations despite repeated court orders and awareness drives. The Delhi government has urged residents to refrain from further bursting crackers and has warned of fines for those caught flouting restrictions. Recurring crisis The post-Diwali haze has become an annual health emergency for the National Capital Region. Experts emphasise that unless local emissions are curtailed and strict enforcement of firecracker and dust-control regulations is maintained, Delhi will continue to suffocate each winter. “Stubble burning has reduced, but it’s no longer the main culprit. What we’re seeing is a city choking itself with its own emissions,” said environmentalist Sunita Narain. “The solution lies in year-round enforcement, not just post-festival firefighting.”

दिल्ली की ज़हरीली हवा के पीछे पंजाब की पराली वाली थ्योरी का सच क्या है?

लगता है कि दिल्ली की जहरीली हवा के लिए पराली को कोसना अब न्यू नॉर्मल हो गया है। ये हर साल की रीत सी बन गई है। इस बार दिल्ली में दीवाली के बाद प्रदूषण का रिकॉर्ड टूट गया। दुनिया के सबसे प्रदूषित शहरों में इसका नंंबर आ गया तो इसका ठीकरा फोड़ने के लिए सिर ढूंढे जाने लगे। फिर हुआ ये कि दीवाली के अगले दिन दिल्ली सरकार के पर्यावरण मंत्री मनजिंदर सिंह सिरसा ने बाकायदा प्रेस क़ॉन्फ्रेंस करके आरोप लगा दिया कि आम आदमी पार्टी ज़बरदस्ती किसानों के मुँह बांधकर तरन तारन और बठिंडा में पराली जलवा रही है ताकि दिल्ली के अंदर इसका असर हो। वैसे राजनीतिक आरोप-प्रत्यारोपों से इतर अगर डेटा पर नजर दौड़ाएं तो सेंटर फॉर साइंस एंड एनवायरनमेंट के आंकड़े बता रहे हैं कि सर्दियों के सीजन में दिल्ली में जो पॉल्यूशन बढ़ जाता है, उसमें पंजाब, हरियाणा और पश्चिमी यूपी के खेतों में जलने वाली पराली का योगदान महज 8.1 परसेंट है। सबसे ज्यादा 51.5% योगदान तो गाड़ियों से निकलने वाले धुएं का है। उसके बाद पड़ोसी जिलों से उत्सर्जन का 34.9% और धूल का 3.7% परसेंट योगदान है। जाहिर है, दिल्ली की हवा खराब करने में पराली का योगदान इतना नहीं है, जितना उसका हौव्वा खड़ा किया जा रहा है और वो भी सिर्फ पंजाब की पराली का जबकि वहां तो इस बार खरीफ की फसल ही चौपट हो गई। असली चैलेंज तो आगे है जब रबी की फसल तैयार होगी। विशेषज्ञों का कहना है कि जब तक सरकारें मिलकर प्रदूषण के असली कारणों पर काम नहीं करतीं, तब तक हवा की समस्या का स्थायी समाधान नहीं होगा।

Delhi’s failure to act against the biggest source of its air pollution – vehicles

According to a study by the Centre for Science and Environment, high-congestion traffic can increase emissions between three and seven times, including emissions of certain pollutants, such as carbon, carbon dioxide and nitrogen oxides. n January 2024, Delhi’s average air quality index was “abnormally high”. Low wind speeds slowed the dispersal of pollutants, leaving the city with its worst January air in five years. In its office in central Delhi, members of the Commission for Air Quality Management convened for their first meeting of the year. The central government formed the body in 2021, under the aegis of the ministry of environment, to ensure better coordination of air quality management between Delhi and the National Capital Region, as well as adjoining states in matters of air pollution that affected the capital. To this end, it was vested with the power to issue directions to authorities in this region.

Smog, fireworks, and silent violations:Delhi’s AQI enters severe zone as Supreme Court’s green cracker window overlooked; experts warn of 48-hour toxic spell post-Diwali

Environmental experts warn that even so-called “green crackers” contribute significantly to short-term particulate spikes. “The concept of green fireworks is relative they emit fewer pollutants than traditional ones but are far from clean,” said a researcher from the Centre for Science and Environment (CSE). The national capital is once again cloaked in a toxic haze, with air quality plummeting to “severe” levels as pollution levels crossed the 370 mark on the Air Quality Index (AQI) on Monday evening. According to real-time data from aqi.in, PM2.5 concentrations hovered around 255 µg/m³, while PM10 touched 330 µg/m³, making the air “extremely hazardous” for all age groups. In pockets such as Anand Vihar, Jahangirpuri, and Rohini, AQI readings soared beyond 600, reflecting sporadic but alarming spikes in toxicity. Even a few minutes outdoors, experts warn, could trigger respiratory distress, eye irritation, and fatigue among vulnerable populations.

Diwali fireworks choke Delhi: 36 stations hit ‘red zone’, 4 record AQI above 400

Environmental groups, including Centre for Science and Environment (CSE), urged stricter enforcement of cracker bans and long-term investment in public transport and green zones. While the Environment Ministry has insisted that GRAP measures would help “stabilise” conditions, experts remain sceptical given the recurring post-festival spikes.​ As residents across Delhi celebrated Diwali with fireworks late into Monday night, the capital’s air quality nosedived to the ‘very poor’ and ‘severe’ categories by Tuesday morning. The Central Pollution Control Board (CPCB) recorded an overall Air Quality Index (AQI) of 347 at 7 a.m., with 36 of 38 monitoring stations falling in the red zone. Major hotspots such as Wazirpur (423), Dwarka (417), Anand Vihar (404), and Jahangirpuri (407) registered ‘severe’ pollution levels, while even residential zones like Lodhi Road and ITO hovered around 340–350. Despite Supreme Court restrictions allowing only green firecrackers for limited hours, emissions rose sharply, prompting the continuation of Stage II of the Graded Response Action Plan (GRAP) across Delhi-NCR. Capital Engulfed in Toxic Smog Thick grey smog blanketed Delhi’s skyline on Tuesday morning – a haunting ritual that follows every Diwali celebration. Visibility dropped below 100 metres in some neighbourhoods, and the air carried an acrid smell of burnt powder. By 8 a.m., Delhi’s average AQI stood at 350 , marking one of the worst post-Diwali mornings in three years. CPCB’s SAMEER app indicated that several areas breached the AQI 400 mark, reflecting hazardous pollution levels. Fire stations received over 260 calls overnight, mostly for minor blazes triggered by fireworks, but no serious injuries were reported. DPCC officials confirmed that unregulated firecracker bursting continued beyond the permissible 8 p.m. to 10 p.m. window. Delhi Chief Minister Rekha Gupta reiterated her appeal for public cooperation, stating, “This is not just a policy matter anymore – it’s a public health emergency in slow motion.” Health experts warned that prolonged exposure could aggravate respiratory diseases, especially among children and the elderly.​ Rising Pollution Despite Crackdown Efforts In the days leading up to the festival, authorities had enforced preventive action under GRAP Stage II, banning most construction and dust-inducing activities. The Supreme Court, while allowing green crackers between October 18 and 20, aimed to strike a balanced approach between tradition and sustainability. However, enforcement faltered as non-compliance remained widespread. According to data from SAFAR and CPCB, particulate matter (PM2.5) concentration stood at more than 15–18 times the safe limit of 60 µg/m³ across north and central Delhi on Tuesday morning. Officials attributed the spike to meteorological factors, including stagnant wind speeds below 5 kmph and reduced atmospheric dispersion. Experts also flagged the onset of stubble burning in Punjab and Haryana as contributing to the pollution surge. The CAQM has warned that without rain or stable winds, Delhi’s air could remain in the ‘severe’ category throughout the week. Last year, the city had reported an average post-Diwali AQI of 359, nearly similar to this year’s levels, indicating minimal progress despite intensified awareness campaigns. Human Cost and Call for Responsibility Residents took to social media with visuals of dense smog around India Gate and Connaught Place, expressing frustration at the recurring pattern. “We are gasping, not living,” one Delhiite wrote on X (formerly Twitter), echoing a sentiment of helplessness and anger. Public health experts highlighted that elevated PM2.5 levels pose serious risks even for healthy adults, linking Delhi’s air quality spikes to rising cases of asthma, bronchitis, and cardiovascular complications. Environmental groups, including Centre for Science and Environment (CSE), urged stricter enforcement of cracker bans and long-term investment in public transport and green zones. While the Environment Ministry has insisted that GRAP measures would help “stabilise” conditions, experts remain sceptical given the recurring post-festival spikes.​ The Logical Indian’s Perspective Year after year, the morning after Diwali serves as a painful reminder that celebration without restraint can darken the very skies we wish to light. Delhi’s deepening smog is not just a matter of air quality but a mirror to collective accountability. While bans and policies play their part, real transformation begins with empathy – the willingness to prioritise public well-being over momentary pleasure.

55 pc of Hyderabad still outside air quality monitoring network

Hyderabad: Despite efforts under the National Air Quality Programme (NAQP) to strengthen air quality monitoring, nearly 55% of Hyderabad’s area remains uncovered, making it difficult to track and control emissions. Currently, the city has 10 Continuous Ambient Air Quality Monitoring Stations (CAAQMS). However, experts say that this number is far below the requirement. According to the Centre for Science and Environment (CSE), which conducted a recent study, Hyderabad needs at least 30 CAAQMS stations to effectively monitor air quality across the Greater Hyderabad region, in line with CPCB guidelines that recommend station numbers based on population size. The main pollutants measured by these monitoring centres include sulphur dioxide (SO₂), nitrogen oxides (NOx), ozone (O3), carbon dioxide (CO2), and particulate matter PM 2.5 and PM 10. These sensors continuously record the concentration of pollutants in the air and send reports to the State and Central Pollution Control Boards (PCB) at regular intervals.

Why Delhi’s PM2.5 levels dropped rapidly post Diwali after hitting 4-year high

Concentration of PM2.5, tiny airborne particles that can get absorbed into the bloodstream and pose significant health risks, surged by midnight to the second-highest recorded in Delhi over the past five Diwalis, but plummeted just as rapidly by Tuesday afternoon. This drop for a post-Diwali day, experts told ThePrint, was mainly because of weather conditions and a lower-than-usual count of farm fires. Central Pollution Control Board (CPCB) data shows that Delhi’s concentration of PM2.5 peaked at an hourly average of 675 micrograms per cubic metres (ug/m3) at midnight on 21 October. But it was down to 82 ug/m3 by 3 pm Tuesday. “It is quite common for Diwali night to see extreme pollution, and then a steep fall the next morning. As the sun rises, the particles start dissipating. Also, the winds were favourable and since it was not too cold, particulate matter did not stay in the air for too long,” said Shambhavi Shukla, programme manager at think-tank Centre for Science and Environment (CSE). The same trend in real-time PM2.5 levels held up across monitoring stations in the city. At RK Puram, a residential area sandwiched between the Outer and Inner Ring Roads, PM2.5 logged a high of 1,476 ug/m3 at midnight and fell to 117ug/m3 by Tuesday afternoon.

Delhi air pollution spikes post-Diwali: What is the way out?

Delhi and its neighbouring regions are facing dangerously high air pollution levels during Diwali. The Federal’s Editor-in-Chief S Srinivasan hosted the latest Capital Beat panel, featuring Prof Gufran Beig, Chair and Founder of SAFAR; Soumya Sarkar, senior Journalist; and Dr Rajesh Chawla, Pulmonology & Critical Care, Indraprastha Apollo Hospitals, Delhi. The discussion focused on rising AQI levels, health hazards, and potential mitigation strategies. Extreme air quality and monitoring Most monitoring stations in Delhi and the National Capital Region reported air quality index (AQI) readings above 450, classified as “severe plus”. Experts warn that these levels could persist until January, making the city one of the most hazardous places to live, particularly for children, the elderly, and individuals with underlying health conditions. Prof Beig explained the technical limits of AQI measurements: “When it comes to 999, that means the monitor is set to a maximum of 1000, and the last reading it can show is 999 because it cannot touch 1,000.” He noted that some stations recorded values exceeding 1700–1800, reflecting extreme pollution spikes. Health impact of particulate matter Dr. Chawla described the effects of particulate matter on the lungs. Fine particles such as PM2.5 penetrate deep into lung tissue and can trigger inflammation, chronic obstructive pulmonary disease (COPD), bronchial asthma, coronary artery disease, and strokes. He noted that high pollutant levels exacerbate symptoms, increase medical interventions, and prolong recovery from infections. He highlighted a seasonal surge in respiratory illnesses during winter months due to stagnant air, low humidity, and pollutants carried from neighbouring states: “There is a 20% increase in patients, particularly those suffering from respiratory illnesses, during this period.” Even healthy individuals experience long-term effects, with repeated exposure potentially shortening life expectancy by several years and increasing risks for lung cancer, vascular diseases, and chronic respiratory conditions. Contributing factors to winter pollution Soumya Sarkar emphasised multiple causes of Delhi’s winter pollution, including vehicle emissions, industrial activity, construction dust, Diwali firecrackers, and stubble burning in Punjab, Haryana, and western Uttar Pradesh. She also highlighted meteorological conditions such as low wind speeds and temperature inversion that trap pollutants over the region. Prof Beig cited data from the Centre for Science and Environment: vehicular emissions contribute 51.5% of pollution, emissions from neighbouring districts 34.9%, farm fires 8.1%, and dust 3.7%. He stressed that while meteorology is uncontrollable, reducing human-generated emissions remains critical. Experts noted the increasing role of Diwali firecrackers in worsening pollution. The scale of bursting has grown exponentially over the past 15 years, surpassing public awareness campaigns and regulatory interventions. Limitations of green crackers The panel discussed the Supreme Court’s permission for limited use of “green crackers,” intended to reduce emissions. Experts warned that green crackers still emit 60–70% of pollutants compared to conventional firecrackers. Prof Beig explained: “Green crackers are not a lasting solution. They reduce emissions partially, similar to switching from diesel to petrol or CNG, but they still contribute significant pollution.” Authorities face difficulty enforcing restrictions due to the open market for these products and widespread public participation during the festival. Long-term mitigation strategies Experts called for a comprehensive “air shed” approach that transcends political and administrative boundaries. This strategy would coordinate actions across all affected districts and states to target emissions from transport, biomass fuel, dust, and industry. Prof Beig stressed: “Unless you are attacking the root cause of emissions with air shed–based strategies, the problem is not going to be solved in a shorter time.” Quick fixes like smoke towers, water guns, or artificial rain provide minimal relief and are insufficient for sustained improvement. Soumya Sarkar added that bipartisan political support is essential for meaningful progress. Without multi-party consensus on pollution control as a public health priority, short-term gains will not materialize. The human cost of prolonged exposure Prolonged exposure to Delhi’s polluted air has measurable impacts on health efficiency and life expectancy. Dr. Chawla explained that repeated exposure prevents the body from adapting, intensifying respiratory and cardiovascular disease risk. Non-smokers face health risks comparable to smokers in other regions due to constant pollutant inhalation. Experts highlighted the persistent strain on medical infrastructure, with patients requiring increased medication and extended recovery periods. Children, the elderly, and individuals with chronic diseases are particularly vulnerable. The panel emphasised that while some short-term measures may reduce pollution spikes, only sustained, coordinated policies addressing emission sources can ensure long-term public health improvement.

Why Delhi air quality plunged after Diwali despite ‘green’ crackers

New Delhi: Delhi woke up on Tuesday to a blanket of thick, grey smog — the familiar post-Diwali haze that once again smothered the city despite the Supreme Court’s order allowing only “green” firecrackers. The night sky had glowed with rockets and colourful fireworks, but by dawn the air had turned heavy, hazy, and hard to breathe. At 8 a.m., the national capital’s Air Quality Index (AQI) stood at 350, categorised as “very poor.” Across the city, 36 of 38 monitoring stations entered the red zone, with areas such as Dwarka (417), Ashok Vihar (404), Wazirpur (423) and Anand Vihar (404) touching “severe” levels. By late morning, visuals from Akshardham and India Gate revealed a city cloaked in haze. Polluted mornings: A recurring Diwali trend Post-Diwali pollution spikes have become an annual ritual for Delhi. Nov 1, 2024: AQI 359, per SAFAR data. Nov 13, 2023: AQI 438, after residents defied the cracker ban. Oct 25, 2022: AQI 315 (very poor). Nov 5, 2021: AQI 454 (severe), with widespread ban violations. At Anand Vihar, one of Delhi’s most polluted spots, AQI this year reached 360, barely an improvement over previous years (396 in 2024, 312 in 2023, 356 in 2022). Eat carrots, sing or pray in Delhi’s smog Green crackers: A promise that failed to deliver The Supreme Court first imposed a ban on firecrackers in 2014–15, citing public-health risks, but enforcement has remained weak. This year, in an attempt to balance industry interests and citizens’ health, the Court permitted only green crackers — said to emit 30 per cent less pollution — between 8 p.m. and 10 p.m. However, celebrations went on well past midnight. Traditional firecrackers were still sold in open markets, and residents across Delhi and its suburbs defied the time and material restrictions. “Thirty per cent less pollution still means poison,” said environmental activist Bhavreen Kandhari, who has campaigned for clean air for nearly three decades. “Are you saying ‘less poison’ is acceptable? I’ve fought for clean air even before my children were born — and still managed to give them damaged lungs.” Data tells the same story Delhi’s 24-hour average AQI on Monday stood at 345 (very poor), up from 326 the previous day. Transport emissions contributed 15.6 %, while industrial sources added 23.3 %, according to the Decision Support System (DSS). The World Health Organization recommends PM 2.5 exposure not exceed 15 µg/m³ over 24 hours — but parts of Delhi recorded levels 24 times higher. Weather and stubble worsen the mix Experts say Delhi’s toxic air each winter is a deadly blend of: Stubble burning in Punjab and Haryana, Vehicular emissions, Dust and industrial output, and Low wind speeds that trap pollutants near the ground. Even before Diwali, AQI had already crossed 300 for several days. On Sunday, authorities invoked Stage II (GRAP-2) of the Graded Response Action Plan, restricting diesel generators and solid-fuel burning. Why the smog persists Environmentalists argue that piecemeal bans and temporary measures fail to address the underlying crisis. “Delhi needs year-round enforcement and regional coordination,” said an air-quality expert from the Centre for Science and Environment. “Without tackling stubble, transport, and construction dust together, even a total firecracker ban won’t clear the skies.”

Delhi Chokes Again: Diwali 2025 Triggers Worst Air Quality in Three Years Despite Crackers Ban

New Delhi, October 22, 2025 — The capital woke up under a thick toxic haze the morning after Diwali, with air quality deteriorating to the “severe” category across most monitoring stations. According to the Central Pollution Control Board (CPCB), Delhi’s overall Air Quality Index (AQI) touched 612, marking the worst post-Diwali pollution in the last three years. Despite repeated government warnings, awareness campaigns, and a blanket ban on firecrackers, illegal fireworks lit up Delhi’s skies late into the night, undoing weeks of progress in air quality improvement efforts. “Every year we repeat the same cycle — warnings, bans, violations, and emergency steps. What we need is strict on-ground enforcement and behavioral change,” said Sunita Narain of the Centre for Science and Environment (CSE).

Toxic Haze Chokes Delhi Despite ‘Green’ Diwali Efforts

New Delhi woke to a familiar post-Diwali nightmare today as a toxic haze chokes Delhi, blanketing the national capital in a pungent smog that pushed air quality deep into the ‘Severe’ category. The pollution spike occurred despite a Supreme Court-mandated ban on traditional firecrackers, rendered ineffective by widespread violations overnight. The city’s average Air Quality Index (AQI) surged to 445 at 8:00 AM IST, a drastic jump from the 305 (“Very Poor”) recorded just 24 hours prior. This alarming spike is attributed to a combination of emissions from illegal firecrackers, a resurgent contribution from farm fires, and meteorological conditions that trapped pollutants near the ground. Key Facts: The Morning After ‘Severe’ Air Quality: Delhi’s average AQI hit 445 (Severe) at 8:00 AM, Oct 21. Several hotspots, including Anand Vihar and RK Puram, recorded levels nearing 480. (Source: CPCB) Hazardous Particle Levels: PM2.5 (fine particulate matter) levels crossed 600 µg/m³ in many locations post-midnight, more than 10 times the 24-hour national safe limit of 60 µg/m³. (Source: SAFAR) Ban Breached: Widespread bursting of illegal, high-emission firecrackers was reported across the National Capital Region (NCR), defying the official ban. Dual Drivers: While firecrackers caused the sharp overnight spike, analysis attributes 18% of the PM2.5 load to stubble burning in neighboring states, creating a high pollution baseline. (Source: SAFAR) Emergency Response: The Commission for Air Quality Management (CAQM) has activated GRAP Stage IV measures, banning non-essential construction and the entry of most trucks into Delhi. A Predictable Emergency: The Data The grim data released this morning confirms the fears of environmentalists and health experts. The Central Pollution Control Board (CPCB) real-time dashboard showed a rapid deterioration in air quality as Diwali celebrations peaked on Monday night. Data 1: City-Wide AQI Spike (Oct 20 vs. Oct 21) The city’s 24-hour average AQI, which stood at 305 (Very Poor) at 4:00 PM on October 20, breached the ‘Severe’ threshold (401+) by 1:00 AM and settled at 445 by 8:00 AM on October 21. Hotspots Veer into ‘Severe Plus’ Several monitoring stations recorded air quality far exceeding the “Severe” mark, a level that affects healthy people and seriously impacts those with existing diseases. Anand Vihar: 480 RK Puram: 472 Punjabi Bagh: 475 Mundka: 478 The primary pollutant in all locations was PM2.5, fine particulate matter small enough to lodge deep in the lungs and enter the bloodstream. Data 2: Peak PM2.5 Concentration The System of Air Quality and Weather Forecasting and Research (SAFAR), managed by the Indian Institute of Tropical Meteorology (IITM), reported that PM2.5 levels in many areas saw a “dramatic spike” between 1:00 AM and 4:00 AM on October 21. Concentrations peaked at over 600 µg/m³, a level considered hazardous by any international standard. (Source: SAFAR Bulletin, Oct 21, 2025, . For context, the World Health Organization‘s (WHO) 24-hour guideline for PM2.5 is just 15 µg/m³. ‘Green’ Efforts Fail Against Widespread Violations The 2025 Diwali celebration was meant to be different. Following directives from the Supreme Court and the National Green Tribunal (NGT), authorities had imposed a blanket ban on the sale, storage, and use of all firecrackers except “green crackers”—low-emission alternatives developed by CSIR-NEERI. However, enforcement on the ground proved tobe a near-total failure. A City Under Auditory and Chemical Assault Residents across the NCR, from Ghaziabad to Gurugram, reported incessant bursting of loud, high-emission firecrackers starting early in the evening and continuing well past 3:00 AM. “It sounded like a warzone after 9 PM,” said Rakesh Kumar, a resident of Mayur Vihar Phase 1. “We sealed our windows, but the smoke still seeped in. My six-year-old daughter, who has asthma, was coughing all night. What is the point of these ‘bans’ if they are just on paper?“ Data 3: Enforcement Actions Delhi Police confirmed the challenge of enforcing the ban in a city of 20 million. In a press release issued this morning (Oct 21, 2025), officials reported: 152 arrests made for the sale or use of illegal firecrackers. Over 2,000 kilograms of banned fireworks were seized in targeted raids in the 72 hours leading up to Diwali. Despite these efforts, the volume of illegal fireworks detonated suggests that enforcement only scratched the surface. The ‘Perfect Storm’: Stubble and Meteorology While firecracker emissions were the clear trigger for the overnight spike, experts note they were added to an already-polluted atmosphere. Farm Fires Add to the Burden The SAFAR model, which provides forecasts on the contribution of external pollution sources, painted a concerning picture. “The contribution of stubble burning (biomass fires) from neighboring Punjab and Haryana, which had been low last week, significantly increased to 18% of Delhi’s PM2.5 concentration on October 20,” the SAFAR bulletin stated. (Source: SAFAR-IITM, Oct 21, 2025). This high baseline meant that the additional load from firecrackers was catastrophic. Trapped by the Weather Meteorology played its traditional role as an antagonist. The India Meteorological Department (IMD) reported that “calm, cool” conditions dominated the night. Low wind speeds (5-8 km/h) and a drop in temperature led to a phenomenon known as temperature inversion, where a layer of warm air traps the cold, pollutant-filled air close to the ground, preventing its dispersal. Official Response and Expert Analysis Faced with a public health emergency, the Commission for Air Quality Management (CAQM) convened an emergency meeting early Tuesday. Government Activates GRAP Stage IV The CAQM immediately invoked the final, most severe stage of the Graded Response Action Plan (GRAP). Key measures under Stage IV include: Transport Ban: A complete ban on the entry of all truck traffic into Delhi (except for essentials like LNG/CNG tankers and vehicles carrying essential goods). Construction Halt: A stop on all linear public projects (roads, flyovers) and all other non-essential construction and demolition activities. Advisory: The government has issued a strong advisory urging private companies and government offices to implement 50% work-from-home (WFH) capacity. ‘A Predictable, Systemic Failure’ Experts argue that this annual crisis is no longer a surprise and reflects a deep systemic failure. In a statement, Dr. Anumita Roychowdhury, Executive Director at the Centre for Science and Environment (CSE), criticized the reliance on last-minute measures. What to Watch Next The immediate forecast offers little relief. The IMD predicts that similar calm wind conditions and foggy mornings will persist for at least the next 48 hours. This means the ‘Severe’ haze is likely to linger over the capital until at least Thursday (Oct 23), posing significant health risks to millions. The long-term focus now shifts to the strict ground implementation of GRAP Stage IV and whether neighboring state governments can control the peak of farm fires, which is expected to intensify in the coming weeks. As the toxic haze chokes Delhi, residents are left with a familiar, choking reality, forcing them to choose between celebrating a festival and the fundamental right to breathe clean air.