Delhi air dirtiest among Indian megacities by wide margin: CSE report

Delhi remained India’s most polluted megacity during the 2024-25 winter, with an average PM2.5 concentration of 175 micrograms per cubic meter, according to a report released by the Centre for Science and Environment (CSE) on Tuesday. While this marks a decline from the previous winter’s 189 µg/m³, the city continues to grapple with severe air pollution.

Kolkata ranked as the second-most polluted megacity, recording an average PM2.5 concentration of 65 µg/m³. Other major cities, including Mumbai, Bengaluru, and Kolkata, saw a decrease in pollution levels compared to last winter, while Chennai and Hyderabad reported no significant changes. The winter PM2.5 averages stood at 52 µg/m³ in Hyderabad, 50 in Mumbai, 37 in Bengaluru, and 36 in Chennai.

A separate study by Swiss air quality monitoring company IQAir named Delhi the world’s most polluted national capital for the sixth consecutive year. The World Air Quality Report 2024 revealed that 13 of the 20 most polluted cities globally are in India. The worst-affected city was Byrnihat, on the Assam-Meghalaya border, with an annual average PM2.5 concentration of 128.2 µg/m³.

India ranked among the five most polluted countries, alongside Chad, Bangladesh, Pakistan, and Congo. The country’s average PM2.5 concentration stood at 50.6 µg/m³ in 2024, reflecting a 7% improvement from the previous year’s 54.4 µg/m³. However, six Indian cities still made it to the list of the world’s 10 most polluted.

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The report highlighted severe pollution episodes in northern India, particularly in Delhi, Punjab, Himachal Pradesh, Chandigarh, and Haryana, with extreme levels recorded in November. Crop stubble-burning remained a significant contributor, responsible for up to 60% of PM2.5 pollution during peak periods.

Despite marginal improvements, India continues to battle hazardous air quality, with millions exposed to pollution levels far exceeding WHO safety limits.

(With inputs from PTI)