‘Delhi-NCR most polluted region in N India’

New Delhi: An all-India winter air quality analysis for 2021-2022 carried out by the Centre for Science and Environment determined that in the northern Indian region, Delhi-NCR remained the most polluted sub-region with the worst days here being almost five times the average elsewhere. The sub-regions peak pollution is also almost five times higher than the average peak of the cities in north-eastern India, which is the region with the lowest peak pollution, and around 60% higher than the average peak in cities in the east, the region with the worst regional average.

The analysis was done between October 15 last year and February 28 for the winter air quality tracker initiative of CSE’s Urban Data Analytics Lab. The analysis said the regional profile of winter pollution shows the eastern region is as polluted as Delhi-NCR.

The NCR cities experienced the most severe daily (24-hour average) PM2.5 levels, with Ghaziabad being the worst hit. Delhi, Noida, Faridabad, Greater Noida and Gurgaon suffered among the worst peak pollution (24-hour average) this winter. From the peak 24-hour PM2.5 level perspective, north Indian cities recorded the highest daily pollution levels on average.

According to the analysis, north Indian cities on average recorded 11% lower PM2.5 readings this winter, but the improvement in the sub-region of Delhi NCR was smaller at just about 8%. Delhi-NCR also saw a marginal increase in the average peak 24-hour pollution. The peak pollution rose significantly from the baseline among the cities in the south (24%) and central Indian cities (7%) despite the overall fall in the winter average.

“The widely divergent trend in pollution levels across regions is strongly influenced by local geoclimatic conditions, meteorology and the intensity of pollution. But the emerging trend points towards a national air quality crisis,” said Anumita Roy Chowdhury, executive director (research and advocacy), CSE. “While the regions are battling to meet the national ambient air quality standards, winter conditions are aggravating the problem further.”

From the peak winter pollution perspective, NCR cities completely dominate the list of the most polluted ones with significantly worse 24-hour averages compared with the rest of the country. Ghaziabad witnessed the worst peak (24-hour average) among all the cities this past winter with a recorded PM2.5 level of 647 micrograms per cubic metre, almost 11 times the Indian standard.

In the northern region, the most polluted city in the region during winter was Ghaziabad, with a winter average of 178 micrograms per cubic metre of PM2.5, followed by Delhi with a winter average of 170. The seven following spots were all occupied by neighbouring NCR cities, namely Faridabad, Manesar, Baghpat, Noida, Gurgaon, Meerut and Hapur. Ghaziabad, Noida and Greater Noida saw a decline in the winter average, but registered higher peaks than last winter.