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Kol winter PM2.5 count better than Del’s, best since 2020-’21

Kolkata: Kolkata's air quality improved this winter with the average PM2.5 concentration dropping to 65 micrograms per cubic metre between Oct 2024 and Jan 2025 against 77 micrograms per cubic metre and 85 micrograms per cubic metre in the past two winters, but it still remained the second-most polluted mega city in the country after New Delhi. A new analysis by Centre for Science and Environment (CSE) found a rise in winter air pollution in all Indian mega cities — Delhi, Mumbai, Kolkata, Bengaluru, Hyderabad and Chennai — with the intensity of pollution varying due to differing meteorological conditions. Delhi, positioned in the landlocked Indo-Gangetic Plains, recorded the highest winter pollution levels, followed by Kolkata, at the tail end of the plains. The other cities benefited from more favourable climatic conditions but still experienced a rise in PM2.5 concentrations because of higher emissions, stagnant atmospheric conditions and reduced pollutant dispersion during winter. Kolkata's average PM 2.5 concentration of 65 micrograms per cubic metre was the lowest in four years, but localised pollution peaks were a cause for concern. This winter's peak — 135 micrograms per cubic metre on Nov 2 — was the same as that of the previous winter, but lower than the peaks of the previous two seasons. Among the seven monitoring stations, Ballygunge recorded the highest daily peak at 195 micrograms per cubic metre on Nov 2, indicating persistent localised pollution hotspots. Ballygunge also had the highest number of bad air days, recording 54 instances of ‘poor' and ‘very poor' AQI. Among the other station, Fort William had 29 ‘poor' and ‘very poor' days, Bidhannagar 24, Victoria 17, Rabindra Bharati University 15 and Jadavpur 13. Monitoring station data showed that PM2.5 concentrations during winter exceeded the annual average across all key locations in the city. Ballygunge recorded the highest winter average at 80 micrograms per cubic metre, a sharp increase from its annual average of 51 micrograms per cubic metre. Fort William and Bidhannagar also showed similar spikes, with winter averages of 71 micrograms per cubic metre and 67 micrograms per cubic metre respectively, compared to their annual levels of 49 micrograms per cubic metre and 46 micrograms per cubic metre. Even Rabindra Sarobar, which had the lowest annual average at 39 micrograms per cubic metre, saw its winter levels rise to 54 micrograms per cubic metre. CSE executive director (research & advocacy) Anumita Roychowdhury said the peaking of pollution during winter in any climatic zone signals the underlying issue of persistent air pollution in rapidly urbanising and motorising cities. "The growing impact of local pollution sources intensifies pollution hotspots across urban centres, increasing exposure risks," she said, adding that stricter measures were necessary to address pollution from all sources, especially in cities like Delhi and Kolkata, which face adverse meteorological conditions that increase pollution. "While Delhi's winter air quality often dominates public discourse, rising pollution levels in other megacities remain largely overlooked," said CSE Urban Lab programme officer Sharanjeet Kaur. "Despite some improvement in seasonal trends, winter pollution continues to be high, or is rising locally." Air quality trends indicate that pollution levels in Kolkata begin to rise sharply mid-Nov and persist until the end of Jan.

Pollution worsening in Indian metros

The national capital remained India’s most polluted megacity by a wide margin during the 2024-25 winter with an average PM2.5 concentration of 175 micrograms per cubic metre (µg/m³). However, a Centre for Science and Environment (CSE) analysis found that PM2.5 pollution in the national Capital declined in the 2024-25 winter (October 1 to January 31) compared to the 2023-24 winter (189 µg/m³). Kolkata was the second-most polluted megacity during the 2024-25 winter with an average PM2.5 concentration of 65 µg/m³. Irrespective of their diverse geographic and climatic contexts, Delhi, Mumbai, Kolkata, Bengaluru, Hyderabad and Chennai -- have seen worsening PM2.5 levels during the winter of 2024-25 (October 1, 2024-January 31, 2025). The overall level and the peaking points of pollution have, however, varied across cities depending on the meteorological conditions of different climatic zones. The analysis showed that PM2.5 levels declined in Bengaluru, Mumbai and Kolkata compared to the previous winter but remained the same in Chennai and Hyderabad. The average PM2.5 levels during the 2024-25 winter were 52 µg/m³ in Hyderabad, 50 in Mumbai, 37 in Bengaluru and 36 in Chennai. According to an analysis, Delhi with a winter average PM2.5 level of 175 µg/m³ remains the most polluted megacity by a large margin during winter, even though the winter average has shown improvement over the previous winter. Delhi’s average PM2.5 concentration during winter increased by 1 per cent compared to the average of previous three winters reaching 174 µg/m³, with peak pollution levels surging on November 18, 2024, to 602 µg/m³. In the other five megacities, the average winter PM2.5 level was 65 µg/m³ in Kolkata; 52 µg/m³ in Hyderabad; 50 µg/m³ in Mumbai; 36 µg/m³ in Chennai; and 37 µg/m³ in Bengaluru. Delhi, located in the land-locked Indo-Gangetic Plains (IGP) with adverse meteorology, has recorded the highest level of pollution during winter, Kolkata — also at the tip of the IGP — ranks second. The megacities outside the IGP — Mumbai, Chennai, Hyderabad and Bengaluru — despite having more advantageous climatic conditions and natural ventilation, have also experienced increases in average PM2.5 concentrations. “When compared to the three-year average, Delhi remained the worst performer, with average winter pollution levels continuing to rise, even though by just 1 per cent higher than the average of the last three years,” the analysis said. Delhi recorded its highest daily PM2.5 level in four years, with pollution spiking to 602 µg/m³ on November 18, 2024 -- the steepest 24-hour average since 2021. This marks a 65 per cent increase from last winter’s peak and is 42 per cent higher than the city’s three-year average, highlighting a worsening pollution trend in the capital. CRRI Mathura Road saw a 20 per cent increase in winter pollution concentration, while Ashok Vihar, Vivek Vihar and Gwal Pahari recorded 11-13 per cent rises in PM2.5 levels. Anand Vihar remained the most polluted location in Delhi, recording a winter PM2.5 average of 227 µg/m³. In the NCR region, Loni in Ghaziabad emerged as the worst affected area, with a PM2.5 average of 153 µg/m³, followed by Gwal Pahari in Gurugram at 149 µg/m³. NO ? concentrations spiked sharply, especially in November-December, with Anand Vihar recording a 71 per cent increase from October to December. ITO registered the highest NO ? levels at 167 µg/m³ in December. Compared to the winter of 2021-22, Mumbai, Kolkata and Hyderabad show improvement with their winter PM2.5 levels dropping by 16 per cent, 14 per cent and 16 per cent respectively. Delhi has recorded a 7 per cent reduction in pollution levels compared to the pervious winter, but 5 per cent higher than in 2021-22. Meanwhile, Bengaluru and Chennai have recorded an increase in PM2.5 levels compared to 2021-22, reflecting a worsening trend in air quality. Kolkata and Chennai showed little improvement, with Kolkata’s maximum peak level of PM2.5 stagnating at 135 µg/m³, while Chennai saw a slight reduction from 147 µg/m³ last winter to 119 µg/m³ this year. According to the analysis, in contrast, Hyderabad, Mumbai and Bengaluru recorded reductions in peak/maximum winter pollution levels. Hyderabad showed the most improvement in peak levels, with a 51 per cent drop in PM2.5 levels, down to 89 µg/m³ from 183 µg/m³ last year. Bengaluru followed with a 42 per cent decline, reducing peak levels to 67 µg/m³, while Chennai saw a 19 per cent improvement and Mumbai recorded a 12 per cent drop in its peak level, lowering its PM2.5 from 92 µg/m³ to 81 µg/m³. This winter’s peak daily pollution levels in Kolkata, Chennai and Hyderabad were lower than their previous winter peaks, but still fell under the “poor” AQI category. Kolkata’s winter peak stood at 135 µg/m³ registered on November 2, 2024; for Chennai, it stood at 119 µg/m³ registered on October 31, 2024; and for Hyderabad it stood at 89 µg/m³ registered on November 25, 2024. Air pollution trends differ across India’s megacities, with Delhi and Hyderabad experiencing their worst air quality in November, while other cities saw peak pollution in December and January. January emerged as the most polluted month for Kolkata, Bengaluru and Chennai, with air quality deteriorating further compared to previous months. Mumbai, on the other hand, recorded its worst pollution levels in December. The analysis further stated that Mumbai recorded its lowest winter PM2.5 average (49 µg/m³) in four years, a 24 per cent decline compared to previous winters. With a winter PM2.5 average of 80 µg/m³, Deonar was the most polluted, followed by Shivaji Nagar (76 µg/m³), Malad West (75 µg/m³), Sewri (71 µg/m³) and Borivali and Kandivali (69 µg/m³ each). “Kolkata recorded a seasonal PM2.5 average of 65 µg/m³ -- a 19 per cent decline compared to the previous three winters. Hyderabad’s seasonal PM2.5 average dropped to 52 µg/m³, marking a 5 per cent decline compared to previous winters. Bengaluru recorded a seasonal PM2.5 average of 37 µg/m³, marking a 7 per cent decline compared to the previous three winters. Chennai’s seasonal PM2.5 average stood at 36 µg/m³, showing 1.2 per cent increase compared to the previous three winters,” according to the analysis.

दिल्ली बना देश का सबसे प्रदूषित शहर, जानिए क्या है अन्य महानगरों का हाल? पढ़ें CSE रिपोर्ट

देश की राजधानी दिल्ली में प्रदूषण कम करने के तमाम प्रयास नाकाफी साबित हो रहे हैं। सेंटर फॉर साइंस एंड एनवायरनमेंट (सीएसई) की ओर से मंगलवार को जारी रिपोर्ट के मुताबिक दिल्ली देश का सबसे प्रदूषित महानगर है। प्रदूषण का स्तर 65 फीसद अधिक सेंटर फॉर साइंस एंड एनवायरमेंट (सीएसई) के नए विश्लेषण में सामने आया है कि इस सर्दी में दिल्ली को एक भी दिन साफ ​​हवा नहीं मिली। प्रदूषण का अंदाजा इसी से लगाया जा सकता है कि आठ दिन हवा की गुणवत्ता 'बेहद गंभीर', 12 दिन 'गंभीर' और 68 दिन 'बहुत खराब' रही। 18 नवंबर 2024 को हालात इस हद तक खराब हो गए कि पीएम 2.5 का स्तर 602 माइक्रोग्राम प्रति घन मीटर पहुंच गया। पिछले चार साल पर नजर डालें तो किसी भी दिन दिल्ली की हवा इतनी खराब नहीं रही। पिछली सर्दी के सबसे प्रदूषित दिन से तुलना करें तो इस दिन प्रदूषण का स्तर 65 फीसद अधिक था। वहीं, विश्व स्वास्थ्य संगठन (डब्ल्यूएचओ) की ओर से जारी मानकों पर नजर डालें तो प्रदूषण का यह स्तर 40 गुना अधिक था। प्रदूषित शहरों की सूची में शामिल है इस शहर का नाम सीएसई ने अपनी इस नई रिपोर्ट में दिल्ली समेत छह भारतीय महानगरों का विश्लेषण किया है। इनमें दिल्ली, मुंबई, कोलकाता, बेंगलुरु, हैदराबाद और चेन्नई शामिल हैं।

Delhi में पूर्वी राष्ट्रीय राजधानी की हवा महानगरों में सबसे प्रदूषित: रिपोर्ट

एक नई रिपोर्ट के अनुसार, भारत के महानगरों में 2024-25 की सर्दियों के दौरान प्रदूषण का स्तर बढ़ सकता है। सेंटर फॉर साइंस एंड एनवायरनमेंट (सीएसई) के विश्लेषण में पता चला है कि दिल्ली, मुंबई, कोलकाता, बेंगलुरु, हैदराबाद और चेन्नई में 1 अक्टूबर, 2024 और 31 जनवरी, 2025 को पीएम 2.5, एक प्रमुख प्रदूषक, अपने चरम पर पहुंच जाएगा। “जबकि प्रतिकूल मौसम विज्ञान के साथ भूमि से घिरे इंडो-गंगा के मैदानों (आईजीपी) में स्थित दिल्ली में सर्दियों के दौरान प्रदूषण का उच्चतम स्तर दर्ज किया गया है, कोलकाता, जो आईजीपी के शीर्ष पर है, दूसरे स्थान पर है। मुंबई, चेन्नई, हैदराबाद और बेंगलुरु में अधिक अनुकूल जलवायु परिस्थितियाँ और प्राकृतिक वेंटिलेशन होने के बावजूद, औसत पीएम 2.5 सांद्रता में भी वृद्धि देखी गई है,” रिपोर्ट में कहा गया है। दिल्ली में सर्दियों के दौरान औसत पीएम 2.5 सांद्रता पिछले तीन सर्दियों के औसत की तुलना में 1 प्रतिशत बढ़कर 174 माइक्रोग्राम प्रति क्यूबिक मीटर पर पहुंच गई, जबकि 18 नवंबर, 2024 को प्रदूषण का चरम स्तर 602 माइक्रोग्राम प्रति क्यूबिक मीटर तक पहुंच गया।

Delhi की हवा भारतीय महानगरों में सबसे ज़्यादा प्रदूषित

मंगलवार को जारी एक विश्लेषण के अनुसार, 2024-25 की सर्दियों के दौरान दिल्ली भारत की सबसे प्रदूषित मेगासिटी बनी रही, जहाँ औसत PM2.5 सांद्रता 175 माइक्रोग्राम प्रति क्यूबिक मीटर थी। हालांकि, सेंटर फॉर साइंस एंड एनवायरनमेंट के विश्लेषण में पाया गया कि राष्ट्रीय राजधानी में PM2.5 प्रदूषण 2023-24 की सर्दियों (189 माइक्रोग्राम प्रति क्यूबिक मीटर) की तुलना में 2024-25 की सर्दियों (1 अक्टूबर से 31 जनवरी) में कम हुआ। कोलकाता 2024-25 की सर्दियों के दौरान दूसरा सबसे प्रदूषित मेगासिटी था, जहाँ औसत PM2.5 सांद्रता 65 माइक्रोग्राम प्रति क्यूबिक मीटर थी। विश्लेषण से पता चला कि पिछली सर्दियों की तुलना में बेंगलुरु, मुंबई और कोलकाता में PM2.5 के स्तर में गिरावट आई, लेकिन चेन्नई और हैदराबाद में यह समान रहा। 2024-25 की सर्दियों के दौरान औसत पीएम 2.5 का स्तर हैदराबाद में 52 माइक्रोग्राम प्रति घन मीटर, मुंबई में 50, बेंगलुरु में 37 और चेन्नई में 36 था।

Delhi’s Pollution Declines, Yet Remains a Toxic Threat—What’s Really Going On?

New Delhi: PM2.5 Pollution in Delhi Sees a Decline in 2024-25 Winter According to the latest analysis by the Centre for Science and Environment (CSE), air quality in Delhi saw a slight improvement during the 2024-25 winter season. The report revealed that the national capital experienced a decrease in PM2.5 pollution, with average concentrations falling from 189 micrograms per cubic metre in the 2023-24 winter to 175 micrograms per cubic metre in the most recent winter period, which lasted from October 1 to January 31.

Chemical Pollution: आज की दुनिया में कोई भी जगह सुरक्षित नहीं

डब्ल्यूएचओ के आंकड़ों का हवाला देते हुए भारत के पर्यावरण की स्थिति 2025 रिपोर्ट में कहा गया है कि 2019 में पर्यावरण में मौजूद रसायनों के कारण दुनिया भर में 2 मिलियन मौतें और 53 मिलियन विकलांगता-समायोजित जीवन वर्ष प्रभावित हुए। सेंटर फॉर साइंस एंड एनवायरनमेंट (सीएसई) और डाउन टू अर्थ पत्रिका द्वारा प्रतिवर्ष प्रकाशित की जाने वाली यह रिपोर्ट इस वर्ष के अनिल अग्रवाल संवाद में जारी की गई। भारत के जी-20 शेरपा अमिताभ कांत, योजना आयोग के पूर्व उपाध्यक्ष मोंटेक सिंह अहलूवालिया, प्रबंधन और वित्तीय गुरु राज लिब्रहान और सीएसई महानिदेशक सुनीता नारायण ने रिपोर्ट जारी की। भारत भर से 80 से अधिक पत्रकार और 20 से अधिक विषय विशेषज्ञ भारत के सामने आने वाले पर्यावरणीय मुद्दों और चिंताओं पर चर्चा करने और उन्हें समझने के लिए एक साथ आए।

214 of 406 cities meet 2.5 standards, LS told

Out of 406 cities where PM 2.5 –– fine, respirable particles that are less than 2.56 micron in diameter –– pollution is monitored, only 214 are complying with national ambient air quality standards (NAAQS), the Union environment ministry informed the Lok Sabha on March 17, highlighting the extent of the bad air crisis in the country. Responding to questions from Congress MP and Leader of Opposition, Rahul Gandhi, the minister of state for environment Kirti Vardhan Singh said: “Air quality monitoring is carried out by Central Pollution Control Board (CPCB) and State Pollution Control Boards (SPCB) in 551 cities in the Country. Out of 406 cities measured for PM 2.5 levels in 2023, 214 cities are complying with National Ambient Air Quality Standards. He provided the list of cities by states and UTs where air quality monitoring is carried out; the guidelines for criteria for setting up of air quality monitoring stations; and the list of cities shortlisted for expansion of air quality monitoring network. SPCBs and Pollution Control Committees (PCC) have prepared plan for the expansion of air quality monitoring network in additional 119 cities, Singh added. The NAAQS standard for PM 2.5 is 40 micrograms per cubic metres annually and 60 micrograms per cubic metres daily (in a 24 hour period). India’s annual PM 2.5 concentration was over 10 times the safe limit at 50.6 micrograms per cubic metre (µg/m3) in 2024 compared to 54.4µg/m3 in 2023, according to Swiss air quality technology firm IQAir’s “World Air Quality Report 2024” released last week. The report said Byrnihat on the Assam-Meghalaya border topped the list as it recorded an annual PM 2.5 concentration of 128.2µg/m3. New Delhi (91.8µg/m3) had a higher annual PM 2.5 concentration than N’Djamena, the capital of Chad, (91.6µg/m3) and Dhaka in Bangladesh (78µg/m3). HT, on July 20, 2024, reported that road dust mitigation has been the primary focus of the National Clean Air Programme (NCAP), which was launched in 2019 as the first such effort to set clean air targets for 131 polluted cities and to reduce particulate pollution nationally, with much lower funding for combustion sources that emit pollutants, as per an analysis by a Centre for Science and Environment (CSE) assessment. NCAP was originally planned to tackle both PM10 and PM2.5 concentrations in the 131 non-attainment cities. In practice, only PM10 concentration has been considered for performance assessment. “The NCAP needs to take PM 2.5 as the benchmark for assessing progress of air pollution control. PM 2.5 is more harmful and it is mainly a result of combustion sources. The health benefits are higher when PM 2.5 is taken as benchmark. We are also noticing non-NCAP cities where pollution is problem. It will be better if NCAP has a much wider focus and state and regional clean air action plan are prioritised,” said Anumita Roychowdhury, executive director, CSE. HT reported last July that air pollution could cause deaths even at levels much lower than what is considered the Indian national standard, according to a study published in Lancet Planetary Health. The report found that across 10 major cities in India — Delhi, Ahmedabad, Bangalore, Chennai, Hyderabad, Kolkata, Mumbai, Pune, Shimla, and Varanasi – around 33,000 deaths every year are attributable to PM 2.5 pollution levels that breach the WHO guideline of only 15 micrograms per cubic metres.

10 शहरों पर अध्ययन, दिल्ली-NCR में ओजोन सबसे कमजोर; सीपीसीबी ने एनजीटी को सौंपी रिपोर्ट में किया खुलासा

धरती को सूर्य की हानिकारक पराबैगनी विकिरणों से बचाने वाली ओजोन (ओ3) दिल्ली-एनसीआर में सबसे कमजोर है। राजधानी और मुंबई में देशभर के अन्य शहरों की तुलना में ओजोन सांद्रता में सबसे अधिक वृद्धि देखने को मिली है। इसका खुलासा केंद्रीय प्रदूषण नियंत्रण बोर्ड (सीपीसीबी) ने राष्ट्रीय हरित अधिकरण (एनजीटी) को सौंपी अपनी रिपोर्ट में किया है। राजधानी में ओजोन के बढ़ते स्तर के मामले की कोर्ट जांच कर रहा है। अधिकरण ने दिल्ली स्थित थिंक टैंक सेंटर फॉर साइंस एंड एनवायरनमेंट (सीएसई) की एक रिपोर्ट के आधार पर स्वतः संज्ञान लेते हुए यह मामला उठाया था। उसमें कहा गया था कि 2024 की गर्मियों में देश के 10 प्रमुख महानगरीय क्षेत्रों में हवा में ग्राउंड-लेवल ओजोन का स्तर बढ़ जाएगा। इन क्षेत्रों और शहरों में बंगलूरू महानगर क्षेत्र (कर्नाटक), चेन्नई महानगर क्षेत्र (तमिलनाडु), दिल्ली-एनसीआर, ग्रेटर अहमदाबाद (गुजरात), ग्रेटर हैदराबाद (तेलंगाना), ग्रेटर जयपुर , कोलकाता महानगर क्षेत्र (पश्चिम बंगाल), ग्रेटर लखनऊ (उत्तर प्रदेश), मुंबई महानगर क्षेत्र (महाराष्ट्र) और पुणे महानगर क्षेत्र (महाराष्ट्र) शामिल हैं। सीएसई ने रिपोर्ट में कहा था कि इस वर्ष अब तक दिल्ली-एनसीआर में अध्ययन अवधि के दौरान 176 दिन ऐसे रहे जब जमीनी स्तर पर ओजोन की मात्रा सामान्य से अधिक दर्ज की गई। साथ ही, मुंबई-एमएमआर और पुणे 138 दिन रहे। ऐसे में एनजीटी ने सीपीसीबी और पर्यावरण, वन और जलवायु परिवर्तन मंत्रालय (एमओईएफसीसी) को नोटिस जारी किया था। प्रत्येक स्टेशन पर ओजोन का 1-घंटे की अधिकता 5 फीसदी से अधिक सीपीसीबी ने रिपोर्ट में कहा है कि वर्ष 2023 के दौरान 178 निगरानी स्टेशनों पर ओजोन की निगरानी की गई। इनमें सामने आए आंकड़ों से पता चला कि दिल्ली-एनसीआर और मुंबई महानगर क्षेत्र (एमएमआर) में प्रत्येक एक स्टेशन पर ओजोन का 1-घंटे की अधिकता 5 फीसदी से अधिक मिली। साथ ही, दिल्ली-एनसीआर (15), एमएमआर (10), जयपुर (5) और पुणे (2) में 32 निगरानी स्टेशनों पर ओजोन का 8-घंटे का अतिक्रमण 5 फीसदी से अधिक दर्ज किया गया। रिपोर्ट के अनुसार वर्ष 2024 की गर्मियों के दौरान कुल 178 निगरानी स्टेशनों में से दिल्ली-एनसीआर के 8 स्टेशनों और चेन्नई के 1 स्टेशन में ओजोन की 1 घंटे की अधिकता का 5 फीसदी से अधिक देखने को मिला। यही नहीं वर्ष 2023 के दौरान रात के 10 से सुबह 06 बजे तक ओजोन सांद्रता का अध्ययन किया। इसमें सामने आया कि दिल्ली-एनसीआर और एमएमआर में केवल एक-एक स्थान पर 1 घंटे के मानक से 5 फीसदी से अधिक वृद्धि दर्ज की गई। आठ स्टेशनों में ओजोन का स्तर 5 फीसदी से रहा अधिक राष्ट्रीय परिवेशी वायु गुणवत्ता मानक (एनएएक्यूएस) के अनुसार ओजोन का 1-घंटे की अधिकता 2024 की गर्मियों में दिल्ली-एनसीआर में 57 स्टेशन पर निगरानी हुई। इनमें शून्य से अधिक ओजोन वाले निगरानी स्टेशनों की संख्या आठ रही। यही नहीं इसमें आठ निगरानी स्टेशन ऐसे रहे जहां ओजोन के स्तर में 5 फीसदी से अधिक वृद्धि दर्ज की गई। इन स्टेशन की संख्या 2023 में तीन रही। तब शून्य से अधिक ओजोन वाले निगरानी स्टेशनों की संख्या 19 मिली। इसके अलावा 2023 में 8 घंटे में ओजोन का स्तर मापा गया। इनमें 57 में से शून्य से अधिक ओजोन वाले निगरानी स्टेशन सात रहे। वहीं, 15 स्टेशन में ओजोन के स्तर में 5 फीसदी से अधिक वृद्धि देखने को मिली। ऐसे बनती है ओजोन ओजोन एक द्वितीयक प्रदूषक है जो वायुमंडल में नाइट्रोजन ऑक्साइड (एनओ2) और वाष्पशील कार्बनिक यौगिकों वीओसी के बीच जटिल रासायनिक प्रतिक्रिया से बनता है। यह सूर्य के प्रकाश की उपस्थिति में मानवजनित और जैविक स्रोतों से उत्सर्जित होते हैं। आवासीय और कृषि स्रोतों से उत्सर्जित कार्बन मोनोऑक्साइड (सीओ) और मीथेन (सीएच 4) भी ओजोन निर्माण में भूमिका निभाते हैं। ओजोन परत के प्रमुख स्रोत एनओ2 और वीओसी है।

10 शहरों पर अध्ययन, दिल्ली-NCR में ओजोन सबसे कमजोर; सीपीसीबी ने एनजीटी को सौंपी रिपोर्ट में किया खुलासा

धरती को सूर्य की हानिकारक पराबैगनी विकिरणों से बचाने वाली ओजोन (ओ3) दिल्ली-एनसीआर में सबसे कमजोर है। राजधानी और मुंबई में देशभर के अन्य शहरों की तुलना में ओजोन सांद्रता में सबसे अधिक वृद्धि देखने को मिली है। इसका खुलासा केंद्रीय प्रदूषण नियंत्रण बोर्ड (सीपीसीबी) ने राष्ट्रीय हरित अधिकरण (एनजीटी) को सौंपी अपनी रिपोर्ट में किया है। राजधानी में ओजोन के बढ़ते स्तर के मामले की कोर्ट जांच कर रहा है। अधिकरण ने दिल्ली स्थित थिंक टैंक सेंटर फॉर साइंस एंड एनवायरनमेंट (सीएसई) की एक रिपोर्ट के आधार पर स्वतः संज्ञान लेते हुए यह मामला उठाया था। उसमें कहा गया था कि 2024 की गर्मियों में देश के 10 प्रमुख महानगरीय क्षेत्रों में हवा में ग्राउंड-लेवल ओजोन का स्तर बढ़ जाएगा। इन क्षेत्रों और शहरों में बंगलूरू महानगर क्षेत्र (कर्नाटक), चेन्नई महानगर क्षेत्र (तमिलनाडु), दिल्ली-एनसीआर, ग्रेटर अहमदाबाद (गुजरात), ग्रेटर हैदराबाद (तेलंगाना), ग्रेटर जयपुर , कोलकाता महानगर क्षेत्र (पश्चिम बंगाल), ग्रेटर लखनऊ (उत्तर प्रदेश), मुंबई महानगर क्षेत्र (महाराष्ट्र) और पुणे महानगर क्षेत्र (महाराष्ट्र) शामिल हैं।

Getting the basics right

The MDA Government’s proclamation about turning the state into a 10 billion dollar economy by 2028 is an aspiration – nay a bold ambition for Meghalaya. But every vision or aspiration requires a clear roadmap so that the public can buy into that roadmap and be co-creators of the 10 billion dollar economy. After all, people should be prepared for that economic boost and they should know which are the areas for potential growth where they can participate. In the case of Meghalaya will it be agriculture, horticulture or just the extractive industries like mining which the Government is working hard to revive by adhering to the Supreme Court directive of scientific mining which is yet to be tried out and which is an unknown entity. No one is sure if the investment in scientific coal mining will yield the same returns as rat-hole mining which has turned hundreds of mine owners into millionaires. Also, if coal is to be scientifically mined, how about limestone mining and quarrying? Why should they be allowed the reckless model of mining without any environmental plough-back? These are red flags that ought to be considered as critical for a state that is not environmentally sustainable. Considering Meghalaya’s location as a hilly terrain and its loss of forest cover the rain water run-off is phenomenal but other than a few water conservation projects not much is happening to address deforestation. Some NGOs have been employed to regreen Meghalaya and to reclaim its lost soil but these projects will take a long time before they produce results. Meanwhile, scientific studies by the Centre for Science and Environment have shown that Meghalaya is heading towards a drought situation. The reasons are not far to seek. If over 747 water sources are in a critical condition then it requires drastic measures to revive those sources and that will only happen through reforestation. But that will take its own time. Most forested areas in Meghalaya are now under broomstick cultivation. This is seen especially in West Khasi Hills and parts of East Khasi Hills. Broomstick is easy to grow and requires no effort at all but its impact on the soil and its capacity to suck underground water is legendary. It is unfortunate that the farmers of this state are not told to put a stop to broomstick cultivation. So large is the production today that there is a glut in the market. Naturally the price of broomsticks has slumped. That’s the law of the market. Another important aspect that is needed to boost Meghalaya’s economy is to get investors from outside the state to set up state of the art processing units for pineapple, oranges and other local fruit. These industrial units however need a constant power supply, not the present mode of power supply where power cuts are perennial. If industries have to rely on generators, their production costs will go up. Also, can Meghalaya have water guzzling industries when the state is facing a precarious situation as far as water is concerned? These are emergent issues that need to be red-flagged.

CSE Analysis: Rising Winter Air Pollution Hits All Megacities, Delhi Worst Affected

CSE Analysis: Irrespective of their diverse geographic and climatic contexts, the megacities of India – Delhi, Mumbai, Kolkata, Bengaluru, Hyderabad and Chennai — have seen worsening PM2.5 levels during the winter of 2024-25 (October 1, 2024-January 31, 2025). The overall level and the peaking points of pollution have, however, varied across cities depending on the meteorological conditions of different climatic zones. This has emerged from a new analysis of real time PM2.5 data in these cities during the winter period. The analysis, done by Centre for Science and Environment (CSE), has evaluated pollution trends in peer megacities and provides insights into long-term seasonal variations and annual shifts in particulate pollution during winter. While Delhi, located in the land-locked Indo-Gangetic Plains (IGP) with adverse meteorology, has recorded the highest level of pollution during winter, Kolkata — also at the tip of the IGP – ranks second. The megacities outside the IGP — Mumbai, Chennai, Hyderabad and Bengaluru — despite having more advantageous climatic conditions and natural ventilation, have also experienced increases in average PM2.5 concentrations. Other than Delhi and Chennai, all other megacities have recorded city-wide winter averages that are comparatively lower than the average of the past three winters; but the concentrations across different locations have been high, leading to high exposures. The peaking of pollution during winter in any climatic zone is a sign of the underlying problem of persistent air pollution in these rapidly urbanising and motorising cities. The growing impact of local sources of pollution shows up in the pollution hotspots across these cities, increasing local exposures and risks,” says Anumita Roychowdhury, executive director, research and advocacy, CSE. These cities need stringent action to curb pollution from all sources to meet the clean air standards. But urban centres like Delhi and Kolkata that face an additional challenge of adverse meteorology which enhances the concentrations, need even more stringent action to counter these effects,” Roychowdhury adds. According to Sharanjeet Kaur, programme officer with the Urban Lab at CSE, “While Delhi’s winter air quality often dominates public discourse, rising pollution levels in other megacities remain largely overlooked. Despite some improvement in seasonal pollution trends, winter pollution continues to remain high or has been rising locally.” The Methodology Behind the CSE Analysis This is an assessment of annual and seasonal trends in PM2.5 concentrations for the period October 1 to January 31 in the years 2021-22, 2022-23, 2023-24, and 2024-25. Data points have been cleaned and data gaps addressed based on the USEPA method. The analysis has been done on the basis of real time data available from currently working air quality monitoring stations in Delhi, Kolkata, Mumbai, Chennai, Hyderabad and Bengaluru — 115 continuous ambient air quality monitoring stations (CAAQMS) have been covered. Delhi (40), Kolkata (seven), Mumbai (31), Hyderabad (14), Bengaluru (14) and Chennai (nine) have more than one real time station, therefore city-wide averages have been used for comparative analysis: it is defined as average of all city stations that have been functional for the given study period. The Key Highlights Of The Analysis During this winter, Kolkata and Hyderabad were most polluted after Delhi, while Mumbai, Chennai and Bengaluru saw the fastest worsening of localised pollution levels : Delhi, with a winter average PM2.5 level of 175 microgramme per cubic metre (µg/m³) remains the most polluted megacity by a large margin during winter, even though the winter average has shown improvement over the previous winter. In the other five megacities, the average winter PM2.5 level was 65 µg/m³ in Kolkata; 52 µg/m³ in Hyderabad; 50 µg/m³ in Mumbai; 36 µg/m³ in Chennai; and 37 µg/m³ in Bengaluru. Kaur points out that winter averages cannot be directly compared with a 24-hour average or an annual average. She says: “Indicatively, daily standards for PM2.5 are 60 µg/m³ and annual standards are 40 µg/m³. But city average is not an adequate indicator for high exposures in these cities.” Worst affected locations within megacities have pollution levels 19-60 per cent higher than citywide averages: There is considerable variation in air quality among locations in each megacity, with worst locations being considerably more polluted than the city-wide averages. In Kolkata and Mumbai, for instance, the worst air quality was recorded at Ballygunge and Deonar respectively, where the seasonal average stood at 80 µg/m 3 . Notably, four of the six most polluted locations among the 68 monitoring stations across five megacities were in Mumbai, while the remaining two were in Kolkata. IDA Pashamylaram was the most polluted location in Hyderabad, with the seasonal average at 62 µg/m³. In Bengaluru, the most polluted location was RVCE — its seasonal average was 56 µg/m³. Alandur was the most polluted location in Chennai, with a seasonal average of 47 µg/m³ . When compared to the citywide average, pollution levels in the worst-affected locations within each megacity were significantly higher. Chennai saw a 30 per cent increase, while Bengaluru recorded a 51 per cent rise. Mumbai experienced the highest disparity, with pollution levels 60 per cent higher than the citywide average. In Hyderabad, the worst-affected location had 19 per cent higher pollution, whereas Kolkata and Delhi recorded increases of 23 per cent and 30 per cent, respectively. Longer-term trend in winter averages in mega cities : When compared to the three-year average, Delhi remained the worst performer, with average winter pollution levels continuing to rise, even though by just 1 per cent higher than the average of the last three years. Compared to the winter of 2021-22, Mumbai, Kolkata and Hyderabad show improvement with their winter PM2.5 levels dropping by 16 per cent, 14 per cent and 16 per cent respectively. Delhi has recorded a 7 per cent reduction in pollution levels compared to the pervious winter, but 5 per cent higher than in 2021-22. Meanwhile, Bengaluru and Chennai have recorded an increase in PM2.5 levels compared to 2021-22, reflecting a worsening trend in air quality. Peak winter pollution in Delhi hits worst level in last four years; other cities indicate varying trends: Delhi recorded its highest daily PM2.5 level in four years, with pollution spiking to 602 µg/m³ on November 18, 2024 — the steepest 24-hour average since 2021. This marks a 65 per cent increase from last winter’s peak and is 42 per cent higher than the city’s three-year average, highlighting a worsening pollution trend in the capital. Kolkata and Chennai showed little improvement, with Kolkata’s maximum peak level of PM2.5 stagnating at 135 µg/m³, while Chennai saw a slight reduction from 147 µg/m³ last winter to 119 µg/m³ this year. In contrast, Hyderabad, Mumbai and Bengaluru recorded reductions in peak/maximum winter pollution levels. Hyderabad showed the most improvement in peak levels, with a 51 per cent drop in PM2.5 levels, down to 89 µg/m³ from 183 µg/m³ last year. Bengaluru followed with a 42 per cent decline, reducing peak levels to 67 µg/m³, while Chennai saw a 19 per cent improvement and Mumbai recorded a 12 per cent drop in its peak level, lowering its PM2.5 from 92 µg/m³ to 81 µg/m³. This winter’s peak daily pollution levels in Kolkata, Chennai and Hyderabad were lower than their previous winter peaks, but still fell under the “poor” AQI category. Kolkata’s winter peak stood at 135 µg/m³ registered on November 2, 2024; for Chennai, it stood at 119 µg/m³ registered on October 31, 2024; and for Hyderabad it stood at 89 µg/m³ registered on November 25, 2024. Monthly air quality pattern varies across the megacities: Air pollution trends differ across India’s megacities, with Delhi and Hyderabad experiencing their worst air quality in November, while other cities saw peak pollution in December and January. January emerged as the most polluted month for Kolkata, Bengaluru and Chennai, with air quality deteriorating further compared to previous months. Mumbai, on the other hand, recorded its worst pollution levels in December. Winter is problematic season for all megacities, but the intensity of the problem varies : The days with bad air quality occurred in clusters during the winter season in the megacities. The clustering of bad air days was longer in Delhi, Kolkata and Mumbai, but of shorter duration in Hyderabad, Bengaluru and Chennai. The intensity and duration of these bad air days were long enough in Delhi to get classified as a smog episode. Kolkata registers high number of ‘poor’ AQI days; Delhi remains the worst: Kolkata’s long-term seasonal PM2.5 trend was lower, but it recorded the same number of ‘poor’ air quality days as Delhi. With 15 days of ‘poor’ AQI, Kolkata matched Delhi’s count and also experienced one day of ‘very poor’ AQI. Among the megacities, Chennai had only one day of ‘poor’ AQI, while Mumbai, Bengaluru and Hyderabad recorded zero ‘poor’ AQI days . In terms of cleaner air, Mumbai had only 19 days of ‘good’ AQI, followed by Kolkata with just 11 — the lowest among megacities (excluding Delhi). In contrast, Hyderabad (21 days), Bengaluru (44 days) and Chennai (55 days) recorded higher number of ‘good’ AQI days. Delhi remained the most polluted megacity, registering eight days of ‘severe+’ AQI, 12 days of ‘severe’ AQI, 68 days of ‘very poor’ AQI, and no ‘good’ AQI days this winter.

Ballygunge most polluted part of Kolkata last winter, Fort William and Bidhannagar follow, finds study

Ballygunge in south Kolkata was the most polluted part of the city last winter followed by Fort William area and Salt Lake; found a pan-India study covering metro cities. The study was carried out by a Delhi-based environment think-tank, based on the data generated by Central Pollution Control Board. Winter months are considered most toxic as the pollution levels surge at this time due to a combination of increased emissions, stagnant atmospheric conditions, and reduced pollutant dispersion. ADVERTISEMENT Ultrafine particulate PM 2.5, considered an extremely toxic pollutant having the ability to penetrate deep into the lungs and trigger range of diseases including fatal ones, has been considered as the benchmark in the study carried out by the Urban Lab at the Centre for Science and Environment (CSE) and released on Tuesday; a copy of which is with the correspondent. The study, led by air pollution expert and CSE executive director (research and advocacy) Anumita Roychowdhury, and covering all metro cities of the country pointed out that Kolkata, overall, recorded improvement in its PM 2.5 level this winter (October 2024 to January 2025), compared to last year. However, pockets of the city showed pollution surges much above the national permissible limit this time. Kolkata was second, right behind Delhi, in winter pollution among the metro cities, as per the study. “Despite seasonal improvements, winter pollution levels in Kolkata surged well above annual averages across monitoring locations. Ballygunge remained the most polluted area, with a winter average PM 2.5 level of 80 micrograms per cubic meter, followed by Fort William (71 micrograms) and Bidhannagar (67 micrograms). Even Rabindra Sarobar, the least polluted location (based on data from seven continuous ambient air quality monitoring stations across Kolkata), saw a 29 per cent increase in winter PM 2.5 levels compared to its annual average” reads the report underlining the high pollution trend in winter. The national limit of PM 2.5 is 60 micrograms. Overall, the city recorded “its lowest winter average PM 2.5 level in four years, with a seasonal average of 65 micrograms per cubic meter — a 19 per cent decline compared to the previous three winters”, but remains above national limit. “The growing challenge of particulate pollution in Kolkata remains a concern despite improvements in winter air quality. While the overall seasonal average has improved, pollution spikes continue to be a challenge,” Roychowdhury told this correspondent on Tuesday morning. The study shows that Ballygunge is clearly the most polluted part of the city with highest day reading during last winter with the highest spike of 195 micrograms — more than three times above normal. Incidentally Ballygunge also recorded the highest annual average of PM 2.5 in city during 2024 with a value of 51 micrograms followed by Fort William (49 micrograms). Rabindra Sarobar recorded the lowest with 39 micrograms. The annual national permissible limit of PM 2.5 is 40 micrograms. The report also has found that, during last winter Ballygunge had 54 very poor and poor air quality days out of 123; much above the city average. The study also pointed out that the city faces a “multi-pollutant challenge” with levels of nitrogen dioxide (NO2) — another major pollutant mainly triggered by the vehicles — rising sharply between November and January. “Victoria witnessed the steepest increase, with NO2 levels surging 6.4 times from October to January,” read the study. “These findings underscore the urgent need for a focused strategy to control pollution from key sources and mitigate the winter air quality crisis in Kolkata,” observed the report. Needs stronger policy; air shade pollution control model State pollution board chairman Kalyan Rudra pointed out that the government has been trying a string of measures to combat city pollution but that it would be difficult to cut significantly more pollution unless the regional air shade pollution control model is pursued. “As the World Bank has been pointing out, we need to pursue the regional air shade pollution control mechanism since much of our pollution comes from outside the city; both across state and international borders,” said Rudra. “The city, being at the tip of the Indo- Gangetic plains, gets affected by the pollution generated in the zone, like Delhi; but inadequate policy implementation also contributes to the problem,” explained Roychoudhury to this correspondent. The expert stressed that Kolkata needs to focus on multisectoral action to counter air pollution. “Like the rest of the country, Kolkata has also been focusing on dust control, which is important, but to substantially reduce pollution levels it needs to act as well to counter pollution from transport, waste burning and likewise,” added the expert. “As observed through in-depth chemical characterisation, solid waste and biomass burning are the dominant sources over Kolkata. Such emissions are enhancing ammonia in the air, which in turn helps form a huge amount of particulate matter. We need to target ammonia emission that is producing ultrafine particulate matter through a secondary process,” explained Abhijit Chatterjee, a scientist associated with the union government research organisation Bose Institute and also an advisor to the union government’s flagship National Clean Air Programme.

Not just Delhi: Winter pollution spike across megacities

Irrespective of their diverse geographic and climatic contexts, India’s megacities of India – Delhi, Mumbai, Kolkata, Bengaluru, Hyderabad and Chennai – have seen worsening PM2.5 levels this winter. The overall level and the peaking points of pollution have, however, varied across cities depending on the meteorological conditions of different climatic zone, according to a latest analysis by the Centre for Science and Environment (CSE). The analysis of real-time PM2.5 data in these cities during the winter period (October 1, 2024-January 31, 2025) has evaluated pollution trends in peer megacities to provide insights into long-term seasonal variations and annual shifts in particulate pollution during winter. While Delhi, located in the land-locked Indo-Gangetic Plains (IGP) with adverse meteorology, has recorded the highest level of pollution during winter, Kolkata – also at the tip of the IGP – ranks second. The megacities outside the IGP – Mumbai, Chennai, Hyderabad and Bengaluru – despite having advantageous climatic conditions and natural ventilation, have also experienced increases in average PM2.5 concentrations. Other than Delhi and Chennai, all other megacities have recorded city-wide winter averages that are comparatively lower than the average of the past three winters; but the concentrations across different locations have been high, leading to high exposures. “The peaking of pollution during winter in any climatic zone is a sign of the underlying problem of persistent air pollution in these rapidly urbanising and motorising cities. The growing impact of local sources of pollution shows up in the pollution hotspots across these cities, increasing local exposures and risks,” Anumita Roychowdhury, executive director, research and advocacy, CSE, said in a release.

Delhi's air dirtiest among Indian megacities by wide margin: CSE report

Delhi remained India's most polluted megacity by a wide margin during the 2024-25 winter, with an average PM2.5 concentration of 175 micrograms per cubic metre, according to an analysis released on Tuesday. However, the Centre for Science and Environment analysis found that PM2.5 pollution in the national capital declined in the 2024-25 winter (October 1 to January 31) compared to the 2023-24 winter (189 micrograms per cubic metre). Kolkata was the second-most polluted megacity during the 2024-25 winter, with an average PM2.5 concentration of 65 micrograms per cubic metre. The analysis showed that PM2.5 levels declined in Bengaluru, Mumbai and Kolkata compared to the previous winter but remained the same in Chennai and Hyderabad. The average PM2.5 levels during the 2024-25 winter were 52 micrograms per cubic metre in Hyderabad, 50 in Mumbai, 37 in Bengaluru and 36 in Chennai.