New Delhi: Winter pollution levels up in all regions this winter while Northern India is the most polluted, with Delhi-NCR cities having higher levels than others.

Centre for Science and Environment has carried out an analysis of data from cities in different regions to throw light on the difference between the two winters. This has been a special winter that coincides with the unlocking of the economy post-pandemic.

The northern Indo-Gangetic Plain is most affected. But this year even though the average level of PM2.5 during summer and monsoon months was considerably lower than the last year. The winter PM2.5 concentration has risen compared to the last winter in many cities.

This analysis has considered a total of 99 cities where data availability for two consecutive winters meets the minimum criteria of data completeness requirement.

The analysis is based on publicly available granular real-time data from the Central Pollution Control Board’s website. The data is captured from 248 stations under the Continuous Ambient Air Quality Monitoring System spread across 115 cities in 22 states.

North Indian cities are on average the most polluted in the country as compare to South Indian cities.

Overall winter PM2.5 levels have worsened significantly in 43 cities out of 99 cities. The most prominent among them are Gurugram, Lucknow, Jaipur, Visakhapatnam, Agra, Navi Mumbai and Jodhpur. Kolkata is the only megacity in this group.

Out of the 99 cities, 19 have experienced substantial improvement in the air quality compared to the previous winter. Chennai is the only megacity included in this pool.

A total of 37 cities out of 99 cities, which include mostly the megacities, have not experienced a significant change in their seasonal average.

It is noteworthy that in 37 cities that are otherwise showing stable or declining seasonal average their peak levels have risen significantly. These include Aurangabad, Indore, Nashik, Jabalpur, Rupnagar, Bhopal, Dewas, Kochi and Kozhikode.

In the Northern region, other cities including Delhi have experienced the reverse, that is the increase in seasonal average but a decline in peak.

When put in an order the top 23 polluted cities are from the Northern region. While Mysuru is the least polluted, followed by Satna and Kochia, Ghaziabad is the most polluted city in the northern belt. Satna, Mysuru, Vijaypura, and Chikkamagaluru are only four cities that have met the 24-hour standard during the season. Satna, Maihar and Mysuru are the cleanest cities in the country.

Report findings make it clear that this winter pollution challenge is not limited to one specific region; it is an omnipresent problem and requires urgent action everywhere.

The most polluted cities were located in Delhi-NCR and UP. Eight of the top 10 were UP cities with Ghaziabad and Bulandshahr taking the top slots. Delhi at number five and Bhiwadi at number 10 were the only exceptions.