October has recorded Mumbai’s worst air quality of 2025 so far, with 19 monitoring locations across the city logging their highest daily average PM2.5 levels, according to a new study by the Centre for Research on Energy and Clean Air (CREA). The analysis used data from the Central Pollution Control Board’s (CPCB) Continuous Ambient Air Quality Monitoring Stations (CAAQMS).

The city’s dirtiest air days coincided with Diwali celebrations between October 19 and 21, when firecracker use and stagnant weather combined to push pollution to alarming levels. The worst-hit areas were BKC, Powai, Mulund, and Ghatkopar, where PM2.5 concentrations exceeded 200 µg/m³, while Deonar and Malad breached 300 µg/m³.