Kolkata's air quality recovered sharply on Wednesday, 11 November 2026, after two consecutive days of rainfall washed away the heavy particulate load left behind by Diwali and Kali Puja fireworks. According to data from the Central Pollution Control Board's (CPCB) National Air Quality Data Management System, recorded at 9 am, the city's Air Quality Index (AQI) fell to the 'Satisfactory' category across multiple monitoring stations — a dramatic recovery from the 'Severe' readings logged just days earlier.

AQI Readings Across Monitoring Stations

Among the major stations, Fort William recorded the highest reading at an AQI of 75, followed by Rabindra Sarobar at 73 and Jadavpur at 72. All three readings fall within the 'Satisfactory' band under India's national AQI classification, which runs from 0 to 500. The city had recorded AQI levels between 400 and 500 — firmly in the 'Severe' category — on 8 and 9 November, coinciding with widespread bursting of firecrackers during the festive period.

How Rain Acts as a Natural Air Cleanser

Environmental experts explained that rainfall physically pulls suspended particulate matter — particularly PM2.5 and PM10 — down to the ground through a process known as wet deposition. It also assists in removing certain gaseous pollutants from the lower atmosphere, reducing smog formation and improving visibility. Prominent environmentalist and green technologist Somendra Mohan Ghosh described the turnaround as remarkable. 'What a miracle! Yesterday evening's and today's morning rain sharply brought down Kolkata's AQI to 75, from the 400–500 range recorded on November 8 and 9 during Diwali fireworks celebrations,' he said.

Relief for Vulnerable Residents

The improvement has provided considerable relief to asthma patients, senior citizens, and children — groups that are disproportionately affected when air quality deteriorates into the severe range. Residents across the city have welcomed the return of clearer skies following several days of thick, pollutant-laden air. This comes amid growing concern in India's major cities about post-festive pollution spikes, which have become an annual public health challenge in West Bengal and several other states.

Experts Warn Improvement May Be Temporary

Despite the relief, environmental experts cautioned that the gains could be short-lived as the city heads into the winter months, when cooler temperatures trap pollutants closer to the ground and natural ventilation decreases. They urged residents to avoid high-emission firecrackers and called for greater adoption of certified green crackers during upcoming festive occasions to prevent another severe pollution episode. Notably, the transition to winter — typically accompanied by declining wind speeds — tends to worsen air quality across the Indo-Gangetic Plain, of which Kolkata is a part.

Weather Outlook

The Meteorological Department has forecast scattered rainfall with thunderstorms across Kolkata and several south Bengal districts through Thursday. Conditions are expected to clear from Friday onwards, with dry weather likely to prevail and pave the way for the onset of winter. On Tuesday, Kolkata recorded a maximum temperature of 31 degrees Celsius — 0.5 degrees above normal — while the minimum settled at 24 degrees Celsius, three degrees above normal. Relative humidity ranged between 63% and 95%. Whether the improvement holds will depend on weather patterns and residents' behaviour during the remaining festive season.