Kol air better than some cities’ but not ‘good’: Study
Times of India | 29 November 2025
Kolkata: A decade-long analysis of air quality index (AQI) trends across India's major cities has delivered a stark message: no major Indian city, including Kolkata, met safe air-quality standards at any point between 2015 and Nov 2025. The comprehensive assessment by Climate Trends, based on central pollution control board data, shows that while pollution levels vary by region and season, every major metro stays outside the ‘good' AQI range for most of the year.
Kolkata, often considered cleaner than Delhi and Lucknow, emerges in the report as a city in persistent moderate pollution, with AQI values largely between 80 and 140—well above safe limits. A marginal improvement is visible since 2022, but winter episodes of PM2.5 spikes continue to drag the city back into the ‘poor' category, especially in the southern belt (Jadavpur, Ballygunge) and near the riverfront, finds the analysis by Climate Trends, a research-based consulting and capacity-building initiative.
Delhi remains the nation's pollution capital throughout the decade, with peak AQI levels over 250 in 2016 and still hovering near 180 in 2025. Lucknow, Varanasi, and Ahmedabad show similar high loads, with slow declines after 2019 but no shift to safe levels. The study says that winter pollution in the Indo-Gangetic Plains is not merely due to emissions — it is a meteorological trap. Cold northwesterly winds, weak western disturbances, zero rainfall, and dense urban structures create stagnant air columns that prevent pollutant dispersion.
"As temperatures fall, the inversion layer thickens, creating a stronger barrier that prevents sunlight and wind from breaking through and clearing the air," said Mahesh Palawat, vice-president (meteorology and climate change), Skymet Weather. "India needs sustained, long-term, science-based policy backed by tough decisions," said Palak Balyan, research lead, Climate Trends.
According to S N Tripathi of IIT-Kanpur, cities require intelligent, data-driven interventions. The report underscores a single truth: India's urban air-quality crisis is structural, persistent, and meteorology-driven. Kolkata is better than the north, but still locked in the cycle of winter pollution. Without deep emission cuts, sustained enforcement, and climate-resilient urban planning, no Indian metro will breathe easy.
Compared to the northern Indo-Gangetic cities, Kolkata fares better but remains far from safe, with AQI values typically hovering between 80 and 140, and slipping into the ‘poor' category every winter as dust resuspension, traffic congestion, thermal inversion, and emissions from industrial belts such as Topsia-Tangra and Howrah choke dispersion. Although the city recorded improvements in recent years — thanks to cleaner fuel standards, tighter emission controls, and growing EV adoption — seasonal stagnation, construction du-st, and winter-time inversion layers continue to push pollution into unhealthy ranges.