• Solid Waste Management and Circular Economy

स्वच्छता सर्वेक्षण: एनडीएमसी सुपर स्वच्छ लीग सिटी अवार्ड में पहले पायदान पर

नई दिल्ली नगरपालिका परिषद (एनडीएमसी) शहरी स्वच्छता और सार्वजनिक सेवा उत्कृष्टता के लिए सुपर स्वच्छ लीग सिटी से सम्मानित किया गया है। एनडीएमसी से प्राप्त जानकारी के अनुसार 50 हजार से 3 लाख की आबादी वाले शहरों की श्रेणी में दिल्ली पहले स्थान पर है। एनडीएमसी को गुरुवार को विज्ञान भवन में आयोजित प्रतिष्ठित स्वच्छ सर्वेक्षण 2024-25 पुरस्कार समारोह में राष्ट्रपति द्रौपदी मुर्मू और भारत सरकार के आवास एवं शहरी मामलों के मंत्री मनोहर लाल खट्टर द्वारा सुपर स्वच्छ लीग सिटी अवार्ड से सम्मानित किया गया। गुरुवार को एनडीएमसी की ओर से यह पुरस्कार दिल्ली सरकार के शहरी विकास मंत्री आशीष सूद, एनडीएमसी अध्यक्ष केशव चंद्रा और एनडीएमसी उपाध्यक्ष कुलजीत सिंह चहल ने संयुक्त रूप से ग्रहण किया। एनडीएमसी के अध्यक्ष केशव चंद्रा ने आभार व्यक्त करते हुए कहा कि यह पुरस्कार स्वच्छता, सेवा मानकों और नागरिक उत्कृष्टता में मानक स्थापित करने के एनडीएमसी के निरंतर प्रयासों का प्रमाण है। मैं अपने कर्मचारियों, विशेषकर सफाई सेवकों को बधाई देता हूं, जिनकी अथक मेहनत से हमें यह राष्ट्रीय सम्मान मिला है। यह उल्लेखनीय उपलब्धि एनडीएमसी के अध्यक्ष, उपाध्यक्ष और परिषद सदस्यों के दूरदर्शी नेतृत्व, स्वच्छता सेवकों, स्वच्छता और बागवानी टीमों, इंजीनियर्स विंग, पीएमयू विशेषज्ञों, योजनाकारों के अथक समर्पण और नागरिकों की सक्रिय भागीदारी के कारण संभव हुई है। एनडीएमसी के उपाध्यक्ष कुलजीत सिंह चहल ने भी 50 हजार और 3 लाख की श्रेणी में नई दिल्ली को सबसे स्वच्छ राजधानी बनाने में सहयोग के लिए निवासियों और आगंतुकों का धन्यवाद किया। उन्होंने इस बात पर जोर दिया कि इस सम्मान को प्राप्त करने में समुदाय की सहयोगात्मक भावना महत्वपूर्ण रही है। एनडीएमसी एक स्वच्छ, हरित और स्वस्थ नई दिल्ली के अपने दृष्टिकोण की प्राप्ति के लिए स्वच्छता को बनाए रखने और बढ़ाने, हरित आवरण में सुधार लाने और अत्याधुनिक स्वच्छता तकनीकों को अपनाने के लिए अपनी प्रतिबद्धता की पुष्टि करती है। इस कारण मिला सम्मान--- एनडीएमसी के एक वरिष्ठ अधिकारी ने बताया कि एनडीएमसी ने अपने क्षेत्र में काफी इनोवेशन किया है। यह अवार्ड हमें इनोवेशन, कूड़ा प्रबंधन और तीन आरआरआर के लिए मिला है। आरआरआर पर्यावरण संरक्षण से जुड़ी तीन महत्वपूर्ण अवधारणाएं हैं। रीसाइकिल या पुनः चक्रण या पुनर्चक्रण यानी उपयोग की गई वस्तुओं (जैसे प्लास्टिक, कागज़, धातु आदि) को प्रक्रिया के द्वारा दोबारा उपयोग के लायक बनाना। रीयूज या पुनः उपयोग यानी किसी वस्तु को फेंकने के बजाय दोबारा किसी रूप में उपयोग करना। तीसरा रिड्यूज यानी कमी करना या घटाना इसका आशय है कि ऐसी वस्तुओं का कम से कम उपयोग करना जो पर्यावरण को नुकसान पहुंचा सकती हैं। 2021 में पहले स्थान पर भी रही है एनडीएमसी 2021-22 में एनडीएमसी 1 लाख से 10 लाख की आबादी की श्रेणी में स्वच्छता सर्वेक्षण में पहले स्थान पर भी रह चुकी है। वहीं विगत वर्ष स्वच्छता सर्वेक्षण 2022-23 में एक लाख से अधिक आबादी वाले शहरों में नई दिल्ली म्यूनिसिपल काउंसिल (एनडीएमसी) को 7वीं रैंकिंग मिली थी। डोर टु डोर कूड़ा कलेक्शन के लिए जितने नंबर तय थे, उसमें से एनडीएमसी ने 99 प्रतिशत अंक हासिल किए थे। एनडीएमसी को 5 स्टार गार्बेज फ्री और वॉटर प्लस प्रमाणित सिटी के रूप में भी सम्मानित किया गया था। इस बार की रैंकिंग तो जारी हुई है लेकिन किस श्रेणी में कितने अंक मिले यह खबर लिखने तक वेबसाइट पर जारी नहीं किए गए थे। 2018 से 2023 तक की एनडीएमसी की रैंकिंग 2018--4 2019--5 2020--3 2021--1 2022--3 2023--7 ------------------------------ नंबर वन कैसे बने दिल्ली, क्या है विशेषज्ञ की राय दिल्ली में कचरा प्रबंधन जिस तरह हो रहा है वह बाकी शहरों से अलग है। दिल्ली सरकार या दिल्ली नगर निगम कचरा प्रबंधन तकनीक से सुलझाने का रास्ता ढूंढ रही है। लेकिन, यह नाकाफी है। अगर दिल्ली को बेहतर करना है तो लोगों को एक साथ लाना होगा। उन्हें कचरा प्रबंधन के बार में समझाना होगा। घरों से ही गीला और सूखा कचरा अलग करना जरूरी है। यही नहीं, जो कचरा घरों से उठाया जाता है वह भी डंपिंग ग्राउंड तक अलग-अलग जाना चाहिए। लेकिन, अभी ऐसा नहीं हो रहा है। इस पर ध्यान देने की जरूरत है। कचरा प्रबंधन का कोई शॉर्ट कट नहीं है। कचरा उठाने वाली गाड़ियों को भी इस तरह बनाना होगा, जिसमें गीला और सूखा कचरा अलग किया जा सके। अतिन बिस्वास, कार्यक्रम निदेशक, ठोस अपशिष्ट प्रबंधन एवं चक्रीय अर्थव्यवस्था, सेंटर फॉर साइंस एंड एनवायरमेंट

• Industrial Pollution

When cost trumps clean air

Ten years after creating rules to make thermal power plants cleaner, the Union Ministry of Environment and Forest has decided to go easy on the power sector. It has tweaked the norms, exempting most power units from installing costly equipment to clean up the coal exhaust, arguing that such instruments are not required for them. Plants in critically polluted areas or non-attainment cities will be evaluated on a case-by-case basis while all other units — accounting for 79% of India’s thermal power capacity — are exempt from mandatory FGD installation, as stipulated in the 2015 rules. With criticism mounting, the ministry issued a clarication, stating that the decision was based on studies conducted by the Indian Institute of Technology, Delhi, the CSIR’s National Environmental Engineering Research Institute in Nagpur, and the National Institute of Advanced Studies (NIAS) in Bengaluru. “The revised sulphur dioxide emission policy is not a rollback of environmental safeguards, but a pragmatic, scientically justied shift towards more targeted, cost-effective and climate-coherent regulation,” the ministry says. Indian coal has a very high ash content (42%), compared to imported coal, which has less than 10%. However, domestic coal contains little sulphur (less than 0.5%) compared to imported coal, which has more than 2% of it. The ministry claims 94% of electricity generated by thermal power plants is fuelled by Indian coal, and this may be the reason for very low ambient sulphur dioxide levels in Indian cities. Therefore, according to the government, further ltering of sulphur oxides is not necessary for most plants operated by the public and private sectors. As per the Central Electricity Authority, 44 thermal power plants are equipped with FGDs, while another 233 FGDs have been awarded out of 537 power plants identied for installation. Retrotting of the equipment in each operating plant requires shutdown times of more than 45 days. The NIAS in its report – that also takes into account the conclusions of IIT Delhi and NEERI studies - recommends a halt for FGD installations for the time being because of low-sulphur content of Indian coals, 220-275 mt tall stacks (vertical distance from the ground to top of the chimney) of thermal power plants, and tropical climate. The institute suggests studies to assess the impact of FGDs in controlling secondary particulate matter pollution from 32 thermal power plants located within 10 km of cities with a population of more than 10 lakh which have either installed FGDs or are at various stages of installing them. energy at the Centre for Science and Environment, a Delhi-based think tank, tells DH. The ministry argues that nationwide retrotting of India’s coal-based capacity for ensuring compliance with the previous SO₂ norms is projected to cost over Rs 2.54 lakh crore in capital expenditure (around Rs 1.2 crore per MW of installed capacity). “In light of the limited incremental benet to ambient PM2.5 levels and the high marginal cost of pollution reduction, such investment must be carefully scrutinised,” it claims, noting that there is barely any difference in sulphur and ambient dioxide concentration in the ambient air of cities with or without FGD. Misinterpretation? However, an analysis released last month by the Centre for Research on Energy and Clean Air states that studies by NEERI, NIAS, and IIT Delhi are being “selectively used to justify inaction” by power plants across the country, which continue to delay the installation of FGD units to control sulphur dioxide emissions. According to the CREA report, the NEERI’s assertion on low levels of ambient sulphur dioxide is “highly misleading”. “The air quality monitoring stations don’t capture the real impact of power plant pollution because they don’t track whether emissions drift upwind or downwind, and they certainly don’t account for chemical reactions that convert SO2 into other pollutants like PM2.5,” says the report. “Using low ambient readings to argue against FGD is not just scientically wrong, it completely misleads about how pollution control works,” it adds. The CREA has also identied loopholes in the IIT report. A 2022 study by IIT Delhi recommended a phased rollout of FGDs across all coal-based power stations, but in their 2024 report, the IIT team contradicted their earlier ndings, relying on data from six cities. “The newer IIT Delhi report recommended halting FGD installations in plants that have yet to adopt them, despite the fact that 92% of plants still lack FGDs. This shift was justied by citing low ambient SO₂ levels and limited impact, overlooking the secondary particle formation,” it says. The ministry’s counter is that such particle formation matters little to ambient air pollution. There are other questions, too. “Exempting all Category C plants from SO₂ norms solely based on location overlooks cumulative pollution, especially in mining areas like Singrauli or Korba, which are not “ofcially” critically polluted areas but are still heavily impacted,” adds the CSE.

• Industrial Pollution

Why govt has exempted 78% of coal-based thermal plants from installing anti-pollution devices

A 2021 analysis by the Centre for Science and Environment (CSE) also contested this claim. It said that plumes from power stations travel long distances of 300 km, and during this time, they get converted to secondary pollutants. The analysis also found that the atmospheric lifetime of SO2 was about 10 days. The Environment Ministry on July 11 exempted the majority of India’s coal-based thermal plants from installing systems that are designed to remove sulphur dioxide (SO2) emissions, a key contributor to air pollution. Known as flue gas desulphurisation (FGD) devices, these systems cut SO2 from flue gas, which is a residue from thermal plants. Of the remaining plants, those around Delhi-NCR have to comply with a December 2027 deadline, and the rest will be asked to fit the devices on a case-to-case basis. Originally, these plants had to install FGD devices by 2017. However, over the years, they have received several extensions to comply. What is the reason behind the Centre’s move? What do the revised rules exactly say? And why have some experts criticised the decision? But first, why are SO2 emissions from thermal plants an issue? Once released into the atmosphere, SO2 usually reacts with ammonia (NH3) to produce ammonium sulfate, which is responsible for roughly one-third of India’s fine particulate matter (PM2.5) pollution, according to recent research by the Centre for Research on Energy and Clean Air (CREA). PM2.5 is injurious to human health as it can lead to chronic diseases such as asthma, heart attack, bronchitis, and other respiratory problems. Direct exposure to high levels of SO2 can irritate the eyes, throat, and lungs. Long-term exposure can result in increased risk of heart attacks, strokes, and premature death, according to CREA. SO2 also affects the environment as it contributes to the formation of acid rain, which can damage ecosystems. One of the biggest sources of SO2 emissions in India is the power sector, especially the coal-based thermal plants. The CREA research found the SO2 levels were higher in 2023 compared to 2019, with a notable increase in regions dominated by coal-based thermal plants. This highlighted “the influence of power plant emissions on air quality”, the research said. What has the government done to address the issue over the years? In 2015, the Environment Ministry notified the first-ever emission norms for control of SO2 and other harmful substances from coal-based thermal plants. These were required to install FGD devices by December 2017. However, this did not happen as the deadline was extended four times at the request of thermal plants. They argued that the installation of FGD devices was costly, and could cause several issues such as disruption of power supply due to shutdown for installation, and an increase in electricity bills. To address these concerns, the Centre amended the emission norms in 2021. It put 596 coal-based thermal plant units (one thermal plant can have multiple units) in three categories. Category A: Plants located within a 10 km radius of the National Capital Region (NCR) or cities having a million-plus population. Their deadline for compliance was 2022. Category B: Plants located within a 10 km radius of critically polluted areas or non-attainment cities. Their deadline was 2023. Category C: Remaining plants whose deadline was 2024. Note that nearly 78% of the plants were put in Category C. About 11% were in Category A, and the rest were in Category B. The latest change in the norms has exempted Category C plants from installing FGD devices. Category A plants, which are in operation and under construction, have to comply by the end of 2027. The Centre will decide compliance for Category B plants on a case-by-case basis. The Environment Ministry has also said that plants which are supposed to retire before December 2030 will not be required to meet the SO2 emission norms, provided they submit an undertaking for exemption. What is behind the latest change in norms? According to the Centre, the change in the norms is based on three studies, which suggest FGD devices are not necessary for coal-based thermal plants. These studies have been carried out by the Indian Institute of Technology–Delhi, the National Institute of Advanced Sciences (NIAS), and the National Environmental Engineering Research Institute (NEERI). The studies have argued against the installation of FGD devices, saying that SO2 levels around the plants are well within the norms prescribed under the National Ambient Air Quality Standards. They have also suggested that the government needs to focus on curbing not just SO2 emissions but rather the overall particulate matter pollution around the plants. The IIT-D and NIAS studies have said that while reducing SO2 emissions, the operation of FGD devices has increased carbon dioxide and PM pollution. All three studies were commissioned by the government or its agencies. For example, the NEERI research was commissioned by NITI Aayog. Why have experts criticised the change in norms? Experts have said that the claim made by the studies that SO2 levels around plants are low is misleading. For instance, CREA in a statement said, “The air quality monitoring stations (CAAQMS) don’t capture the real impact of power plant pollution because they don’t track whether emissions drift upwind or downwind, and they certainly don’t account for chemical reactions that convert SO₂ into other pollutants like PM2.5.” A 2021 analysis by the Centre for Science and Environment (CSE) also contested this claim. It said that plumes from power stations travel long distances of 300 km, and during this time, they get converted to secondary pollutants. The analysis also found that the atmospheric lifetime of SO2 was about 10 days.

• Urban Lab

Informal settlements try out new cool roof solutions to beat the heat

Two summers ago, even with the fans on, sweat would trickle down Rupali Devi’s face and body relentlessly. Now, she can sit home and eat a meal in peace, without having to wipe sweat off every few minutes. Rupali, 23, lives in a 128 sq ft house at Nargis Dutt Nagar slum in Mumbai’s Bandra West with her parents and five siblings. With an asbestos sheet for a roof in a congested neighbourhood, summers felt hotter than they actually were. According to a study by the Centre for Science and Environment (CSE), between the decades of 2001-10 and 2014-23, Mumbai’s summers registered a 0.6°C increase in average ambient air temperature and a 7% increase in humidity. In 2023, cBalance Solutions Hub that works on making low-income houses heat-resilient, installed aluminum foil (Alufoil) pipe motors on Rupali’s roof to reflect heat and light in scorching summers. The initiative has given tremendous relief to the eight residents of the house. Alufoil is a cross-linked polythene foam covered with a low-emissivity, high-reflectivity aluminium coating. The coating restricts the heat emitted inside the space where it is installed. https://www.cseindia.org/decoding-the-urban-heat-stress-among-indian-cities-12191

• DTE - Web

Africa’s Deadliest Climate Crisis In Over A Decade: 2021–2025 Marked By Unprecedented Human Toll

Africa is experiencing an unparalleled climate crisis, with the most catastrophic five-year period in terms of the number of people killed by weather-, climate-, and water-related disasters occurring between 2021 and 2025. Based on a study of the Emergency Events Database (EM-DAT), Down to Earth (DTE) found that 28,759 individuals died and over 221.57 million people were affected during this period, marking Africa’s deadliest climate crisis in over a decade. What is the Extent of Africa’s Deadliest Climate Crisis From 2021 to 2025? The scope of Africa’s climate problem between 2021 and 2025 was astounding. At least 221.57 million persons were impacted, according to DTE’s analysis of EM-DAT data, which is more than the combined totals from 2011–2015 (99.36 million) and 2016–2020 (91.15 million). Twenty-eight thousand seven hundred fifty-nine people died as a result of disasters, more than tripling the 8,106 deaths that occurred between 2016 and 2020. Given the severity of the crisis, these numbers, which are based on data through May 2025, are likely to increase further by the end of the year. Droughts, floods, cyclones, landslides, cold waves, and heat waves were among the extreme weather events that affected the continent, accounting for 54% of the 412 million people affected by catastrophes since 2011.

• Water Programme

Pollution in Delhi stretch of Yamuna spiked in June, as per DPCC

“The pollution level is rising and data show that there is an increase in the amount of untreated sewage entering the river,” said Sushmita Sengupta, senior programme manager (water), Centre for Science and Environment (CSE). The pollution level in the Yamuna river stretch in Delhi increased in June compared with the previous month, according to the Delhi Pollution Control Committee’s (DPCC) monthly water quality report. The 54-km Delhi stretch of the Yamuna is one of the most polluted river stretches in the country. Over the past three decades, the Supreme Court and the National Green Tribunal have passed several orders directing authorities to clean the river. The levels of faecal coliform (microbes from human and animal excreta) and biochemical oxygen demand (BOD) have increased at Asgarpur, the point where the Yamuna exits the city, as per the DPCC report. BOD is the amount of dissolved oxygen consumed by microorganisms to decompose organic matter. A higher BOD implies a greater pollution load. In June, the faecal coliform level in Asgarpur was found to be 24,00,000 MPN (most probable number) per 100 ml, which was 4,800 times the desired limit of 500 MPN/100 ml considered safe for bathing, as per the Central Pollution Control Board. In May, the level was 23,00,000 MPN/100 ml, 4,600 times the desirable limit. Faecal coliform levels at multiple other points of the river have also shown an increase. The level of faecal coliform and BOD at Palla, where the river enters Delhi from Haryana, has also shown an increase in June compared with May, suggesting that the river was more polluted when it entered the national capital. However, at all points in Delhi where water samples were tested, except Palla, faecal coliform levels were found to be above the desirable and the ‘maximum permissible’ levels. “The pollution level is rising and data show that there is an increase in the amount of untreated sewage entering the river,” said Sushmita Sengupta, senior programme manager (water), Centre for Science and Environment (CSE). In May, a report by CSE, a Delhi-based research and advocacy group, noted that the levels of faecal coliform in the Yamuna, an indicator of the sewage load in a river, were so high in Delhi that the river stretch in the Capital was practically a “sewage canal”.

• Urban Lab

High summer-time ozone levels in megacities a cause for concern: CSE study

Ozone levels in all megacities of the country have been high during the summer of 2025, with Bengaluru and Mumbai recording levels above prescribed standards for over a third of summer days, said a new Centre for Science and Environment (CSE) analysis. The new assessment used data from 80 continuous ambient air quality monitoring stations across Mumbai, Kolkata, Bengaluru, Chennai, and Hyderabad. When the CSE analysed Delhi’s ozone (O3) levels last month, they were found to have exceeded the prescribed standard on each summer day between March 1 and May 31. Ozone levels in Bengaluru exceeded prescribed limits 45 out of the 92-day summer days monitored by the CSE, which was a 29 per cent increase compared to last summer, the new analysis said. In Chennai, ozone levels exceeded prescribed levels for 15 out of 92 days, in comparison to no exceedance days for the corresponding period last year. Mumbai recorded ozone exceedance on 32 out of 92 days, marking a 42 per cent decline compared to the corresponding period last year. In Kolkata, about 22 out of 92 days this summer registered an exceedance of ozone standards, which was an improvement over last year by 45 percent. Due to its reactive nature, O3 levels are monitored in an eight-hour average period, instead of 24-hour averages, unlike other pollutants. The prescribed ozone standard for an eight-hour period is 100 micrograms/cubic metre as per the National Ambient Air Quality Standards (NAAQ). Anumita Roychowdhury, executive director, CSE, said, “If unchecked, this can become a serious public health crisis as ozone is a highly reactive gas and can be harmful even with short-duration exposures. In contrast to cities in north India, where high summer temperatures and intense solar radiation can lead to ozone levels exceeding the standards, other cities in warm climates are experiencing consistent ozone exceedance during other seasons as well.” “Ground-level ozone is beginning to emerge as a pollutant of concern with cities experiencing days exceeding the 8-hour standards. While the level of exceedance is expected to be higher during the summer months with strong sun-shine days and heat, this is emerging as a round-the-year problem in the warmer climate. Clean air action plans for cities and the states need to address this multi-pollutant challenge urgently,” CSE recommended in its analysis. Ozone is not a primary, but a secondary pollutant formed through chemical reactions between other pollutants under sunlight. Hence, summer months see a spike in ozone concentrations. These chemicals include nitrogen oxides (Nox), volatile organic compounds, and carbon monoxide (CO), pollutants emitted from vehicle tailpipes, power plants, factories, the CSE analysis stated. Ground-level ozone can affect the airways and lungs adversely, increase susceptibility to infections, worsen respiratory ailments, and decrease lung function.

• Urban Lab

Spring ozone surge prompts warnings for public health

CSE finds Bengaluru recorded 45 ozone-exceedance days this summer —up 29%. Pollution now peaking earlier, with serious implications for health and agriculture Between March and May this year, Bengaluru has recorded a higher number of days exceeding the ozone standard, compared to the previous summer, an analysis conducted by the Centre for Science and Environment in New Delhi has highlighted. As many as 45 out of 92 days this summer recorded ozone levels exceeding permissible limits, according to data from Bengaluru’s air quality monitoring stations. This represents a 29% rise in high-ozone days compared to last summer. The worst day in terms of spatial spread was March 31, when four out of 14 monitoring stations reported levels above the standard threshold. Hombegowda Nagar recorded the maximum number of days with high ozone levels (31 days), followed by Bapuji Nagar. A comparison of ozone levels in May 2025 and May 2024 shows a 28% drop in average hourly ozone peaks, indicating it no longer persists after sunset as it did last year. Daily trends reveal that higher NO2 levels during morning and evening peaks help neutralize ozone. However, ozone concentrations rise during off-peak hours when NO2 levels are comparatively lower, allowing it to accumulate more freely in the atmosphere. Unlike primary pollutants, ozone is not emitted directly from any source. It is formed through chemical reactions involving nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide (CO) - pollutants that are released by vehicles, power plants, factories, and other combustion sources. In the presence of sunlight, these substances undergo a series of cyclic reactions that result in the formation of ozone at ground level. VOCs also have natural sources such as vegetation, adding to the complexity. Ground-level ozone accumulates not only in urban environments but can also travel long distances, turning into a regional pollutant. It can impact agricultural productivity and threaten food security. Experts say that exposure to ground-level ozone can inflame and damage the airways, increase susceptibility to infections, and worsen respiratory conditions such as asthma, chronic bronchitis, and emphysema. Children with underdeveloped lungs, older adults, and individuals with existing respiratory conditions are particularly vulnerable. Ozone exposure increases the frequency and severity of asthma attacks, often leading to higher rates of hospitalisation. In Bengaluru, ozone forms during both winter and summer, but this year’s data shows a notable shift to spring (February–April), with a 31% rise compared to the same period last year. This trend suggests earlier ozone formation, likely driven by rising temperatures, stronger solar radiation, and potential changes in precursor emissions contributing to the seasonal shift. The analysis underlines that ozone is a regional pollutant that requires effective control at both the local and regional levels. According to CSE researchers, Bengaluru’s clean air action plan must include ozone mitigation. This requires scaling up zero-emission vehicles, cleaner industrial processes, and fuels. Authorities must also control waste burning, remediate legacy waste, and promote clean household fuels to reduce emissions and tackle rising ground-level ozone levels effectively. India scenario As per the analysis, every leading metropolis and megacity in India – including Kolkata, Mumbai, Hyderabad, and Chennai – has been struck by high ozone levels in the summer of 2025. Ground-level ozone pollution in all these cities has spiked, and concentrations have exceeded the eighthour standards on a number of days

• Urban Lab

Mega cities in India see high concentration of ozone pollution

All mega cities in India, including Kolkata, Bengaluru, Mumbai, Hyderabad and Chennai, saw high concentration of ground-level ozone pollution this summer season, according to a new analysis by think tank Centre for Science and Environment (CSE). A previous analysis had shown that ozone, instead of particulate matter, was the main pollutant in Delhi’s daily Air Quality Index (AQI) on several days this summer. The new analysis by the CSE’s Urban Lab highlighted that ozone, unlike primary pollutants, is not released directly from any source. It forms through complex chemical reactions involving nitrogen oxides (NOx), volatile organic compounds (VOCs) and carbon monoxide (CO), pollutants emitted by vehicles, power plants, industries and other sources of combustion. These substances react in the presence of sunlight, leading to the formation of ozone at the ground level. Anumita Roychowdhury, executive director at the CSE, said: “If unchecked, this can become a serious public health crisis as ozone is a highly-reactive gas and can be harmful even with short-duration exposures.” She added that while cities in north India experience high ozone levels in summer due to intense heat and strong sunlight, cities in warmer climates are also seeing consistent ozone exceedance in other seasons. The current policy focus must be expanded to include improved monitoring, the mitigation of this toxic gas and a reduction in high local exposures. Ozone mitigation needs drastic control over a range of gases from vehicles, industry and all combustion sources, Roychowdhury said. Sharanjeet Kaur, deputy programme manager at the CSE’s Urban Lab, said: “Inadequate monitoring, limited data and inadequate methods of trend analysis have weakened the understanding of this growing public health hazard across cities of India. Instead of merely averaging out the levels for the city, which is the standard practice to estimate the AQI, it is also important to adequately capture the high levels of local build-up and exposures in the hotspots and design mitigation strategies accordingly.” Between March 1 and May 31 this year, Mumbai recorded ozone exceedance on 32 out of 92 days across its monitoring stations, a 42-per cent drop compared to the same period last year. The worst day in terms of spread was March 29, when eight out of 31 stations reported exceedance. The highest ground-level ozone concentration recorded was 90 micrograms per cubic metre. In Kolkata, ozone levels crossed the safe limit on 22 out of 92 days, a 45-per cent decline compared to last summer. The city also saw an overall improvement, with the average hourly ozone peak dropping by 22 per cent. Bengaluru saw ozone exceedance on 45 of the 92 days, a 29-per cent increase from last year. The worst day was March 31, when four of 14 stations recorded levels above the standard. Hyderabad recorded 20 ozone exceedance days, a 55-per cent drop compared to last summer. The highest ozone level recorded in the city was 51 micrograms per cubic metre. Chennai saw ozone exceedance on 15 days this summer. No such exceedance was reported during the same period last year. In comparison, the city had three exceedance days in 2023 and 19 in 2022. The highest level this year was 64 micrograms per cubic

• Urban Lab

CSE Analysis: Indian Mega Cities Face High Ozone Pollution This Summer

CSE Analysis: Every leading metropolis and mega city in India – including Kolkata, Bengaluru, Mumbai, Hyderabad and Chennai – has been struck by high ozone levels in the summer of 2025. Ground-level ozone pollution has spiked and concentrations have exceeded the eight-hour standards on a number of days. This has emerged from an analysis done by Centre for Science and Environment (CSE), which was released here today. The analysis has been done by the Urban Lab in CSE under its ‘air quality tracker’ initiative. The assessment highlights that unlike primary pollutants, ozone is not emitted directly from any source. It forms through intricate chemical reactions involving nitrogen oxides (NOx), volatile organic compounds (VOCs), and carbon monoxide (CO) — pollutants that are released by vehicles, power plants, factories and other combustion sources. In the presence of sunlight, these substances undergo a series of cyclic reactions that result in the formation of ozone at ground level. VOCs also have natural sources such as vegetation, adding to the complexity. Ground-level ozone accumulates not only in urban environments but can also travel long distances, turning into a regional pollutant. It can impact agricultural productivity and threaten food security. Given ozone’s highly reactive nature, the ambient air quality standards for it are set for eight-hour averages, instead of 24-hour averages. Anumita Roychowdhury, executive director, CSE, says: “If unchecked, this can become a serious public health crisis as ozone is a highly reactive gas and can be harmful even with short-duration exposures. In contrast to cities in north India where high summer temperatures and intense solar radiation can lead to ozone levels exceeding the standards, other cities in warm climates are experiencing consistent ozone exceedance during other seasons as well.” Roychowdhury adds: “The current policy focus must be expanded to include improved monitoring and mitigation of this toxic gas and reduction in high local exposures. Ozone mitigation needs drastic control over a range of gases from vehicles, industry and all combustion sources.” “Inadequate monitoring, limited data and inadequate methods of trend analysis have weakened the understanding of this growing public health hazard across cities of India. Instead of merely averaging out the levels for the city – which is the standard practice to estimate AQI — it is also important to capture adequately the high levels of local build-up and exposures in the hotspots and to design mitigation strategies accordingly ,” says Sharanjeet Kaur, deputy programme manager at the Urban Lab in CSE. The CSE review shows that exposure to ground-level ozone can inflame and damage the airways, increase susceptibility to infections, and worsen respiratory conditions such as asthma, chronic bronchitis and emphysema. Children with underdeveloped lungs, older adults, and individuals with existing respiratory conditions are particularly vulnerable. Ozone exposure increases the frequency and severity of asthma attacks, often leading to higher rates of hospitalisation. The investigation method: This assessment has traced trends during summer (March-May) between 2022 and 2025 (up to May 31). It is based on publicly available granular real time data (15-minute averages) from the Central Pollution Control Board’s official online portal – the Central Control Room for Air Quality Management. The data has been captured from 80 official stations under the Continuous Ambient Air Quality Monitoring System (CAAQMS), spread across Mumbai (31), Kolkata-Howrah (12), Bengaluru (14), Hyderabad (14) and Chennai (nine). Says Kaur: “Given the volatile and highly localised nature of ground-level ozone pollution build-up and its variability across space, and consistent with the global good practice, this analysis has considered station-level trends in terms of number of days exceeding the eight-hour standard over time.” She points out that as ozone formation depends on complex atmospheric chemistry and on photochemical reactions, its level varies across the time and space horizon. Meteorological parameters such as sunny and warm weather, stagnant wind patterns etc have a bearing on its formation. Kaur says: “This analysis tracks exceedances at each station in metro cities — breach of the standard by even one station is considered exceedance by the metro city in which the station is located. Days with multiple stations exceeding the standard indicates the severity of the spatial spread and number of people exposed.” The study has considered global good practice and taken on board the USEPA approach of computing eight-hour averages for a day and then checking for the maximum value among them to capture the daily ozone pollution level. USEPA assesses city-wide or regional AQI based on the highest value recorded among all stations of the city or the region. Thus, trends have been calculated in terms of number of days when the daily level has exceeded the eight-hour standard (referred as exceedance days hereafter.

• Urban Lab

रिपोर्ट : हाथ से निकल रहे हालात, साल भर झेलना होगा धूल-धुएं का गुबागुबार

भारत के कई शहरों मेंओजोन षण बढ़ रहा है, जिसमेंबेंगलु में 29% की वृद्धि ई है। सीएसई की रिपोर्ट के अनुसार, यह षण गर्मियों तक सीमित नहीं हैऔर वाय पर गंभीर भाव डाल सकता है।...

• Solid Waste Management and Circular Economy

कूड़े से बनी बायो सीएनजी से हर रोज चल सकती हैं 17 हजार कारें, इतना पैदा होता है कूड़ा

विज्ञान एवं पर्यावरण कें की रिपोर्ट के अनुसार, दिली मेंहर दिन पांच हजार 210 टन गीला कचरा पैदा होता है। इतनेकूड़े सेबनी बायो सीएनजी सेहर रोज 17 हजार कारेंचल सकती हैं। अगर ठीक सेउपयोग किया जाए तो राजधानी मेंपैदा होनेवाला कचरा बत फायदेमंद साबित हो सकता है। गीलेकचरेसेहर दिन एक लाख 74 हजार किलो बायो सीएनजी बनाई जा सकती है। बायो सीएनजी की यह मात्रा इतनी बड़ी हैकि इससेहर दिन सह हजार सेयादा कारों की धन खपत पूरी हो सकती है।

• Urban Lab

दिल्ली-बेंगलुरु समेत भारत के इन शहरों में ओजोन प्रदूषण जानलेवा! CSE की रिपोर्ट में खुलासा

सेंटर फॉर साइंस एंड एनवायरनमेंट (CSE) की नई रिपोर्ट ने दिल्ली, कोलकाता और बेंगलुरु जैसे भारत के बड़े शहरों के लिए चिंता बढ़ा दी है. CSE की रिपोर्ट में खुलासा हुआ है कि दिल्ली समेत भारत के कई बड़े शहरों में ओजोन प्रदूषण गंभीर स्तर पर पहुंच गया है. इन शहरों में दिल्ली, मुंबई, कोलकाता, बेंगलुरु, चेन्नई और हैदराबाद भी शामिल है. रिपोर्ट में बताया गया है कि ओजोन प्रदूषण अब केवल गर्मियों की समस्या नहीं है, बल्कि सर्दियों में भी ओजोन स्तर मानकों से ऊपर है. इसका सीधा असर शहरों के वायु की गुणवत्ता पर पड़ा है, जिससे हवा में धूल और धुएं का घना गुबार बना रहता है. इस गर्मी के दौरान देश के कई शहरों में ओजोन प्रदूषण खतरनाक स्तर पर पहुंच गया. साथ ही कई दिनों तक इसका स्तर सामान्य से ज्यादा रहा.

• Urban Lab

दिल्ली-बेंगलुरु समेत भारत के इन शहरों में ओजोन प्रदूषण जानलेवा! CSE की रिपोर्ट में खुलासा

सेंटर फॉर साइंस एंड एनवायरनमेंट (CSE) की नई रिपोर्ट ने दिल्ली, कोलकाता और बेंगलुरु जैसे भारत के बड़े शहरों के लिए चिंता बढ़ा दी है. CSE की रिपोर्ट में खुलासा हुआ है कि दिल्ली समेत भारत के कई बड़े शहरों में ओजोन प्रदूषण गंभीर स्तर पर पहुंच गया है. इन शहरों में दिल्ली, मुंबई, कोलकाता, बेंगलुरु, चेन्नई और हैदराबाद भी शामिल है.

• Urban Lab

दिल्ली, बेंगलुरु, मुंबई समेत भारत के इन शहरों में ओजोन प्रदूषण हुआ जानलेवा, CSE की रिपोर्ट में खुलासा

सेंटर फॉर साइंस एंड एनवायरनमेंट (CSE) की हालिया रिपोर्ट ने दिल्ली, कोलकाता और बेंगलुरु जैसे प्रमुख भारतीय शहरों में ओजोन प्रदूषण (Ozone pollution) की गंभीर स्थिति को उजागर किया है. रिपोर्ट के अनुसार, दिल्ली के साथ-साथ मुंबई, कोलकाता, बेंगलुरु, चेन्नई और हैदराबाद में ओजोन प्रदूषण चिंताजनक स्तर पर पहुंच गया है, जो इन शहरों के निवासियों के स्वास्थ्य और पर्यावरण के लिए एक बड़ा खतरा बन सकता है.

• Urban Lab

New Delhi: समय पर कार्रवाई न हुई तो प्रदूषण बनेगा संकट: CSE

नई दिल्ली: भारत के बड़े शहरों जैसे कोलकाता, बेंगलुरु, मुंबई, हैदराबाद और चेन्नई में इस गर्मी (2025) में जमीन के स्तर पर ओजोन प्रदूषण ने खूब सिर उठाया है. सेंटर फॉर साइंस एंड एनवायरनमेंट (CSE) की नई रिपोर्ट के मुताबिक, इन शहरों में ओजोन का स्तर कई दिनों तक 8 घंटे के मानक से ज्यादा रहा. यह प्रदूषण इतना खतरनाक है कि यह लोगों के स्वास्थ्य और खेती पर बुरा असर डाल रहा है. इस समस्या को समझते हैं और जानते हैं कि क्या करना जरूरी है.