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New Delhi, August 24, 2022: The summer of 2022 was not only unusually hot but also uncharacteristically high on particulate pollution, especially in north India. High PM2.5 levels were observed across multiple cities and regions, and pollution has not been confined to a few mega cities or a specific region -- it is a widespread national problem.
This has emerged from the analysis of summer air quality undertaken as part of the air 2 quality tracker initiative of the Urban Lab at Centre for Science and Environment (CSE). Summer days from March 1 to May 31 have been considered for the analysis, as rains had set in during June in several regions. As availability of real time air quality data has improved in several regions with expansion of the air quality monitoring systems, it has become possible to assess the regional differences and understand the unique regional trends.
“This analysis identifies the unique patterns of pollution across all regions and puts a spotlight on a large number of towns and cities that do not get policy attention. Summer particulate pollution spikes due to arid conditions, high summer heat and temperature, and more airborne dust particles that travel long distances compounding the problem from local sources,” says Anumita Roychowdhury, executive director, research and advocacy, CSE.
“This air quality tracker initiative has helped to benchmark the summer air quality for peerto-peer comparison within each region and understand the inter-regional differences that need to inform policy action. Several regions experienced high particulate pollution when heat wave conditions were also widespread and intense,” says Avikal Somvanshi, senior programme manager at the Urban Lab.
Data analysis: This analysis is based on publicly available granular real time data (15- minute averages) from the Central Pollution Control Board’s (CPCB) official online portal, Central Control Room for Air Quality Management. The data is captured from 356 official stations under the Continuous Ambient Air Quality Monitoring System (CAAQMS) spread across 174 cities in 26 states and Union territories.
Even though there are multiple real time monitors in a few cities, many could not be considered for this summer air pollution analysis due to data gaps and lack of quality data. Moreover, in several cases, the real time monitors have been set up recently and therefore, long term data is not available. Several cities of south and northeastern regions have procured their real time monitors in April 2022. Questions on quality are being raised due to cases like the one where the CPCB has reported the same data for Aurangabad in Bihar and Aurangabad in Maharashtra.
Regional divisions:
Key findings
North India is the most polluted, with Delhi-NCR being the summer pollution hotspot: Summer average PM2.5 for North India stood at 71 µg/m³, the highest among all the regions. East India with 69 µg/m³ summer average was the second worst. West India (54 µg/m³) and Central India (46 µg/m³) also recorded summer level access of 40 µg/m³. Northeast India (35 µg/m³) and South India (31 µg/m³) were the cleaner compared to other regions.
Within North India, Delhi NCR was found to be most polluted sub-region. The cities of Delhi-NCR recorded very high summer PM2.5 averages, with Bhiwadi reporting the highest summer average of 134 µg/m³. Manesar (119 µg/m³), Ghaziabad (101 µg/m³), Delhi (97 µg/m³), Gurugram (94 µg/m³) and Noida (80 µg/m³). The PM2.5 average of NCR region is almost three times the average of the cities in southern India.
Daily peak pollution was highest in east India, with cities of Bihar recording the highest levels: Summer daily peak PM2.5 levels for East India stood at 168 µg/m³, the highest among all the regions. North India with 142 µg/m³ summer peak was the second worst. West India (106 µg/m³), Central India (89 µg/m³), Northeast India (81 µg/m³) and South India (65 µg/m³) also recorded summer peak in access of 60 µg/m Within North India, Delhi NCR was found to be most polluted sub-region.
The cities of Bihar recorded very high summer PM2.5 averages, with Bihar Sharif reporting the highest summer peak of 285 µg/m³. Katihar (245 µg/m³) and Patna (200 µg/m³) also recorded peak level in access of 200 µg/m³. Rohtak recorded the highest peak pollution in North India with a 258 µg/m³ daily peak. It is important to note that mega cities are not the most polluted in any of the regions, it is the smaller and upcoming cities that are pollution hotspots.
Average pollution this summer is higher than the previous summer: The regional PM2.5 levels this summer is higher compared to previous summer in North, Central, East and West regions, says Somvanshi. PM2.5 levels stagnated in South India while Northeast registered a decline.
North India have recorded a staggering 23 per cent increase in seasonal PM2.5 level compared to the previous summer based on an average of cities that have valid daily PM2.5 concentration data of both summers (1 March to 31 May). Within North India, NCR was the worst performing sub-region with 25.8 per cent increase in seasonal PM2.5 level. Central India registered increase of 15.6 per cent while West India (4.2 per cent) and East India (1.8 per cent) registered increase under five per cent. South India showed no change in the seasonal average but saw a decline of 22 per cent in seasonal peak. Northeast India registered drop in both seasonal average (-12.8 per cent) and seasonal peak (-18.3 per cent). East India was the only region which registered an increase in its seasonal peak compared to last summer
Smaller cities and towns dominate the most polluted list for this summer: Bhiwadi in Rajasthan was the most polluted city in India this summer with seasonal average of 4 134 µg/m³. Manesar in Haryana was the second most polluted city with a seasonal average of 119 µg/m³. Singrauli in Madhya Pradesh is the third most polluted city with seasonal average of 110 µg/m³. Rohtak, Haryana and Muzaffarnagar, UP are the other cities in the top five most polluted cities.
12 cities of Delhi-NCR feature in top 20 cities with highest pollution levels this summer. From peak summer pollution perspective Northern Haryana cities completely dominate the list of most polluted with significantly worse 24-hr averages compared to rest of the cities. Aizwal in Mizoram and Gummidipoondi in Tamil Nadu were the least polluted cities in the country this summer.
North India
Northern cities with increasing summer pollution trends: 19 cities in the region show increasing trend, i.e. both summer average and peak increased compared to their previous summer. Hapur in Uttar Pradesh saw a staggering spike of 210 percent in the summer average and a peak average increase of 265 per cent. It was followed by Kaithal in Haryana that registered 123 per cent increase in summer average and 96 per cent increase in peak. Other cities that show increase include Muzaffarnagar, Panchkula, Kurukshetra, Rohtak, Ambala, Mandi Gobindgarh, Manesar, Udaipur, Yamuna Nagar, Bahardurgarh, Hisar, Gurugram, Kota, Ludhiana, Lucknow, Khanna, and Meerut.
Northern cities with mixed trend in the average and peak levels during summer: 23 cities in the region show mixed trend, i.e. their summer average has increased but the peak pollution declined compared to their previous summer. Only Bhatinda is showing decline in their summer average (11 per cent) and increase of one percent in peak pollution compared to last summer. Narnaul has the most divergent trend as its peak average declined by 52 per cent but its summer average is 12 per cent higher. Charki Dadri in Haryana show the most increase of 85 percent in their summer average and registered 27 per cent lower peak pollution followed by Chandigarh, Kanour, Dharuhera, Jaipur, Patiala, Ajmer, Delhi, Karnal, Faridabad, Noida, Narnaul, Jind, Bhiwadi, Palwal, Bulandshahr, Amritsar, Jodpur, Greater Noida, Sirsa, Alwar, Ghaziabad, and Bhatinda.
Cities recording declining trend in summer pollution: Seven cities show declining trend, i.e. both summer average and peak decreased compared to their previous summer. Varanasi in Uttar Pradesh saw the highest decline with a drop of 59 per cent in their summer average and 64 per cent lower peak. Other cities with declining trend include Ballabgarh, Jalandhar, Pali, Agra, Mandikhera, and Srinagar.
Cities with highest summer pollution in the Northern region: The top 12 most polluted spots are occupied by neighboring Delhi- NCR cities. Most polluted city in the region during summer was Bhiwadi with summer average of 134 μg/m3 followed by Manesar that had a summer average of 119 µg/m³. Other cities include Rohtak, Muzaffarnagar, Bahadurgarh, Charkhi Dadri, Delhi, Hisar, Dharuhera, Faridabad, Yamuna Nagar, and Gurugram. Cities of Delhi-NCR completely dominated the list of the 5 most polluted. Rohtak in Haryana shows the highest peak of 258 µg/m³ followed by Mandi Gobindgarh in Punjab with a 240 µg/m³ summer peak
Cities with least summer pollution in the Northern region: Srinagar has recorded levels that are lowest in the region. Other cities with a lower summer average include Gorakhpur, Varanasi, and Prayagraj in UP. However, all northern cities—aside from Gorakhpur in Uttar Pradesh and Srinagar in J&K—had peak summer pollution levels that were higher than the 24-hr standard limit of 60 µg/m³.
East India
Cities with increasing summer pollution trend in the Eastern region: Four cities in the region show increasing trend, i.e. both summer average and peak increased compared to their previous summer. Muzaffarpur in Bihar saw a jump of 24 per cent in the summer average and 14 per cent increase in peak. Hajipur in Bihar registered 11 per cent increase in summer average and 7 per cent increase in peak. Other cities are Durgapur and Haldia in West Bengal.
Cities with mixed trend in the average and peak summer pollution levels: Three cities in the region show mixed trend, i.e. their summer average increased but peak pollution declined compared to their previous summer except Howrah in West Bengal which saw a summer average drop of five per cent while seeing an eight per cent increase in peak pollution levels compared to the previous summer. Patna in Bihar saw a summer average increase of 20 per cent and a decline of 7 per cent in the peak followed by Gaya in Bihar with 16 per cent decline in the peak average and a summer average increase of five per cent.
Cities with declining summer trend in the Eastern region: Three cities in the region show declining trend, i.e. both summer average and peak decreased compared to their last summer. Siliguri in West Bengal saw the most decline with a drop of 21 per cent in their summer average and 43 per cent lower peak. Kolkata also registered decline -- summer average declining by 12 per cent and peak by 2 per cent.
Cities with highest summer pollution in the Eastern region: Most polluted city in the region include Katihar in Bihar with summer average of 95 µg/m³. It is followed by Patna in Bihar with summer average of 91 µg/m³ and Durgapur in West Bengal with 84 μg/m3. The next ten most polluted spots were occupied by the small cities of Bihar. Arrah in Bihar is the least polluted with summer average of 49 µg/m³. All the cities of West Bengal except Durgapur showed their summer average below the standard limit of 60 µg/m³.
Cities with least summer pollution in the Eastern region: Haldia and Kolkata in West Bengal recorded the lowest summer average among the cities of the region. All the cities in the region have recorded peak pollution levels above 24-hr standard.
West India
Cities with increasing trend in Western region: Three cities in the region show 6 increasing trend, in both summer average and peak levels compared to the previous summer. Pune in Maharashtra saw a jump of 42 per cent in the summer average and 31 per cent increase in peak. Ankleshwar in Gujarat registered 36 per cent increase in summer average and 10 per cent increase in peak. Mumbai in Maharashtra registered 18 per cent increase in summer average and 12 per cent increase in peak.
Cities with declining trend in Western region: Six cities in the region show declining trend, i.e. both summer average and peak levels, compared to the previous summer. Vatva in Gujarat saw the most decline with a drop of 33 per cent in their summer average and 45 per cent lower peak. It is followed by Navi Mumbai where the summer average declined by 28 per cent and peak by 49 per cent. Other cities that show declining trend include Nashik, Ahmedabad, Gandhinagar, and Chandrapur.
Cities with highest summer pollution in the Western region: Most polluted city in the region was Gandhinagar with seasonal average of 68 µg/m³. Next two spot were occupied by Ahmedabad and Pune.
Cities with least summer pollution in the Western region: Nashik in Maharashtra recorded the lowest summer average in the region followed by Navi Mumbai, Nagpur, and Chandrapur. Other than Nashik, all the cities in the region saw peak pollution levels above the standard limit of 60 µg/m³.
Central India
Cities with increasing summer trend in Central region: Six cities in the region show increasing trend in both summer average and peak levels compared to the pervious summer. Mandideep in Madhya Pradesh the most divergent trend with summer average increasing by 40 per cent but its peak was 94 per cent higher. Gwalior registered 35 per cent increase in summer average and 12 per cent increase in peak. Other cities that show increasing trend include Jabalpur, Ratlam, and Ujjain.
Cities with mixed trend in average and peak levels: Six cities in the region show mixed trend, i.e. their summer average have increase but peak pollution decline compared to the previous summer or visa-versa. Dewas in Madhya Pradesh registered 30 per cent increase in summer average and 20 per cent drop in peak. It is followed by Bhopal with summer average increase by 23 per cent but its peak was 17 per cent lower. Damoh and Satna had decline in summer average by 5 and 19 per cent but their peak was 49 and 28 per cent higher.
Cities with declining summer trend in Central region: Only two cities in the region show declining trend, i.e. both summer average and peak decreased compared to the previous summer. Sagar in Madhya Pradesh saw the most decline with a drop of 48 per cent in their peak average and five per cent lower summer average, followed by Singrauli with one per cent decline in summer average and 19 per cent lower peak.
Cities with highest summer pollution in the Central region: Most polluted city in the region was Singrauli with summer average of 110 µg/m³. Next two spot were occupied 7 by Katni and Ujjain. Singrauli with peak 24-hr level of 198 µg/m³ had highest peak pollution in the region.
Cities with least summer pollution in the Central region: Satna and Bilaspur recorded the lowest summer average and peak average in the region while, all the other cities in the region saw peak pollution levels above the standard limit of 60 µg/m³.
Southern India
Cities with increasing trend in the Southern region: Eight cities in the region show increasing trend, i.e. both summer average and peak increased compared to their previous summer. Kozhikode saw a jump of 76 percent in summer average and 17 per cent increase in peak. Kochi has the most divergent trend with 55 per cent increase in the summer average but its peak increase by 145 per cent. Other cities with increasing trend in the region are Madikheri, Bengaluru, Puducherry, Amravati, Chikkaballapur, and Thiruvananthapuram.
Cities with mixed trend in average and peak levels: Six cities in the region show mixed trend in their summer average and peak pollution level compared to the pervious summer. Tirupati in Andhra Pradesh saw increase in summer average by 19 per cent but its peak decline by 23 per cent. Chennai and Hyderabad also recorded mixed trend with summer average increase by 14 and 10 per cent but their peak was lower by 11 and 7 per cent. Visakhapatnam registered no change in summer average but its peak lower by one per cent. Other cities with mixed trend in the region are Hubbali, and Yadgir.
Cities with declining trend in Southern region: Five cities in the region show declining trend, -- both summer average and peak decreased compared to their previous summer. Gummidipoondi in Tamil Nadu saw the highest decline with a drop of 65 per cent in their summer average and 57 per cent lower peak. Mangalore shows the most divergent trend with decline in peak average by 73 per cent and summer average decline by 31 per cent. Other cities with declining trend are Kannur, Rajamahendravaram, and Kollam.
Cities with highest summer pollution levels in the Southern region: Most polluted city in the region was Hyderabad with summer average of 47 µg/m³. It is are followed by Bengaluru with 40 µg/m³.
Cities with least summer pollution in the Southern region: Gummidipoondi in Tamil Nadu and Vijaypura in Karnataka recorded the lowest summer average in the region. All the cities in the region had their summer average lower than the 24- standard limit of 60 µg/m³
Northeast
India Cities with mixed trends in the Northeast: Agartala in Tripura show mixed trend, i.e. their summer average registered no change but its peak pollution declined by 12 per cent compared to their last summer.
Cities with declining trend in the Northeast: Two cities in the region show declining trend in summer average and peak levels compared to the previous summer. Aizwal in Mizoram saw the most decline with a drop of 57 per cent in their respective summer averages and 55 per cent lower peak. Guwahati registered 13 per cent decline in its summer average and peak level declining by 28 per cent.
Cities with highest summer pollution levels in Northeast region: Most polluted city in the region include Guwahati with summer average of 56 µg/m³. This is followed by Agartala that registered summer average of 45 µg/m³.
Cities with least summer pollution in Northeast region: Aizwal recorded the lowest summer average in the region.
The way forward
Says Roychowdhury: “Overall, seasonal pollution is expected to be highly variable due to the impact of local and regional pollution, and meteorological and climatic impacts that need to inform policy making. Due to arid and heat conditions and growing desertification, summer months usually witness high dust impacts. But the dust is also a carrier of toxic substances from combustion sources including vehicles, industry, power plants and burning of waste. While the local nature of this problem needs to be investigated in all regions, this requires significant tightening of action to control emissions from each pollution source as well as massive efforts to combat desertification, improve soil stabilisation, green-walling through afforestation, and reduce the heat island effect in cities.”
For details and interviews etc, please contact Sukanya Nair of the CSE Media Resource Centre: sukanya.nair@cseindia.org, 8816818864
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