During last winter, 204 out of 238 Indian cities recorded average PM2. 5 (a key pollutant) levels exceeding the Indian standard of 40 g/m³, according to Central Pollution Control Board (CPCB) data analyzed by the Center for Research on Energy and Clean Air (CREA). According to Finland-based independent research group CREA, Ghaziabad was the most polluted city, with an average PM2.

5 concentration recorded at 172 g/m3, followed by Noida (166 g/m3) and Delhi (163 g/m3). According to the analysis, Greater Noida was the fourth most polluted, followed by Bahadurgarh, Dharuhera, Gurugram, Bhiwadi, Charkhi Dadri and Baghpat.

The top ten most polluted cities include four cities each from Uttar Pradesh and Haryana, along with Delhi and one city from Rajasthan. PM2.

5 (Particulate Matter 2. 5) are respirable fine particles that can enter the lungs and bloodstream and lead to various respiratory and other diseases. The analysis was based on CPCB’s Continuous Ambient Air Quality Monitoring Stations (CAAQMS) data between October 1, 2025, and February 28, 2026.

Moreover, according to the analysis, none of the cities analyzed met the World Health Organization (WHO) PM2. 5 standard of 5 g/m3. “Among India’s megacities, Delhi (163 g/m3), Kolkata (78 g/m3), Mumbai (48 g/m3), and Chennai (44 g/m3) recorded average PM2.

5 concentrations in winter 2025-26 exceeding the national standard. Bengaluru recorded an average PM2.

5 concentration of 39 g/m3, which is below the national standard,” CREA said in a statement. Slightly below NAAQS limits.

” Cleanest city: Chamarajanagar in Karnataka was the cleanest city in India last winter, with an average PM2. 5 concentration of 19 g/m3.

According to the analysis, the ten cleanest cities include eight cities from Karnataka and one city each from Madhya Pradesh and Meghalaya.