CSE releases Winter Air Pollution Analysis for Indian megacities

new delhi: the centre for science and environment (cse) has released its winter air pollution analysis for 2024-25, highlighting worsening pollution levels across india's six megacities—delhi, mumbai, kolkata, bengaluru, hyderabad, and chennai. the findings indicate that air quality deterioration is not confined to delhi but is a growing concern in all major urban centers, despite variations in meteorological conditions.delhi remains the worst-affecteddelhi registered the highest levels of pollution, recording eight days of 'severe+' air quality index (aqi), 12 days of 'severe' aqi, and 68 days of 'very poor' aqi, with no 'good' aqi days this winter. the national capital's average pm2.5 concentration was 175 µg/m³, significantly exceeding safe limits. kolkata followed with 65 µg/m³, while hyderabad, mumbai, chennai, and bengaluru reported winter averages of 52 µg/m³, 50 µg/m³, 36 µg/m³, and 37 µg/m³, respectively.regional variations and key observationsdelhi-ncr and kolkata experienced the maximum pollution trapping due to adverse meteorological conditions.mumbai, chennai, and bengaluru saw the fastest worsening of localized pollution levels post-winter onset.the most polluted locations in each city recorded pm2.5 concentrations up to 60% higher than the respective citywide averages.delhi's highest daily pm2.5 level in four years was recorded on november 18, 2024, at 602 µg/m³.hyderabad showed the most improvement in peak pollution, with a 51% drop in pm2.5 levels compared to the previous winter.call for stringent measurescse emphasized the need for strengthened enforcement under the national clean air programme (ncap) to ensure all cities adopt stricter emission control measures. “rapidly urbanizing and motorizing cities need comprehensive action on vehicular emissions, industrial pollution, power plants, waste burning, and household solid fuel usage,” said anumita roychowdhury, executive director, research and advocacy, cse.sharanjeet kaur, programme officer at cse's urban lab, noted that while delhi's air quality dominates discourse, rising pollution levels in other megacities remain underreported. “despite some seasonal improvements, winter pollution remains alarmingly high in several locations,” she added.the report underscores the urgency for targeted interventions, especially in cities with persistent pollution hotspots. a detailed city-wise analysis is available at https://www.cseindia.org/megacities-winter-pollution-note-march2025.pdf