NEW DELHI: As the winter nears end, an analysis of winter pollution levels shows that smaller cities fared poorer compared to mega cities.
The analysis of real time data by the Centre for Science and Environment (CSE) shows north India is most polluted while cities of the northeast show lower averages but higher toxicity as the share of PM2.5 in PM10 is considerably high in those cities.
The analysis has considered 99 cities where data availability for two consecutive winters meets the minimum criteria of requirement for 75 per cent of data completeness.
Overall, winter PM2.5 levels have worsened significantly in 43 cities out of 99 cities that have valid daily PM2.5 concentration data for over 75 per cent of days for this and previous winters.
This pool of cities mostly consist of Tier-1 or even smaller cities. Most prominent among them are Gurugram, Lucknow, Jaipur, Visakhapatnam, Agra, Navi Mumbai and Jodhpur. Kolkata is the only mega city in this group.
Out of the 99 cities considered, 19 have experienced substantial improvement in their winter air quality compared to the previous winter. Chennai is the only mega city included in this pool.
There is also wide variation in peak pollution level experienced during winter. In about 37 cities that are otherwise showing stable or declining seasonal average their peak levels have risen significantly during winter.
Toxic Air