Not Delhi, this is the most polluted city in north India

Delhi's air pollution issue has always remained a point of concern for residents as well as experts. The city's air quality index (AQI) often reflects that it is one of the most polluted cities in the world. However, a study conducted by the Centre for Science and Environment (CSE) in north Indian cities discovered that it is not Delhi, but Ghaziabad the most polluted city in the region. The CSE's "All India Winter Air Quality Analysis", analyzed 60 north Indian cities during the winter of 2021-22 (from October 15 to February 28) and found out Ghaziabad was the most polluted city among 60 north Indian cities last winter, followed by Delhi.

Ghaziabad's particulate matter was recorded 2.5 (PM2.5) average of 178 microgram per cubic metre (μg/m3), followed by Delhi which had a winter average of 170 ug/m3.

The other polluted cities in north India included--Faridabad, Manesar, Baghpat, Noida, Gurugram, Meerut, and Hapur.

The CSE, however, observed that the north Indian cities have, on average, recorded an 11% lower PM2.5 level last winter, but the improvement in the sub-region of Delhi-NCR was 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," it said.

In the analysis, the cleanest city in north India was found to be Srinagar.

In the eastern part of India, Siwan (Bihar) was the most polluted city while in the western region, Gujarat's Ankleshwar has the worst air quality.

In the central region, Singrauli in Madhya Pradesh was the most polluted city while in the south, Kalaburgi in Karnataka and Hyderabad in Telangana were found to be the most polluted cities.

The most polluted city in the northeastern region was Guwahati in Assam with a winter average PM2.5 of 81 ug/m3.

The analysis was done for the 2021-22 winter air quality tracker initiative of the CSE's Urban Data Analytics Lab.

"The winter pollution challenge is not limited to megacities or to one specific region. It is now a widespread national problem that requires urgent and deliberate action at a national scale, Anumita Roychowdhury, executive director, research and advocacy, CSE said.

The 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 326 official stations under the Continuous Ambient Air Quality Monitoring System (CAAQMS) spread across 161 cities in 26 states and Union territories, it said.

(With PTI inputs)