Kolkata’s air quality deteriorated sharply during Kali Puja-Diwali celebrations, with firecracker emissions pushing fine particulate pollution into the “very poor” range across multiple monitoring stations and raising concerns about prolonged exposure as winter conditions set in.
Central Pollution Control Board data cited in the report showed that all seven air quality monitoring stations in Kolkata recorded “moderate” air quality at 9 pm on Sunday, although Ballygunge and Jadavpur were already nearing the “poor” category. Pollution levels, particularly PM2.5 and PM10, began worsening again after 6 pm following an improvement during the afternoon.
Residents in several parts of the city reported a burning smell and a visible haze caused by cracker smoke. The deterioration followed a similar decline on the previous night, when widespread firecracker use on Diwali eve pushed several continuous ambient air quality monitoring stations into the “very poor” category between 9 pm on Saturday and 2 am on Sunday.
The highest readings were recorded at stations in Salt Lake, Ballygunge and Jadavpur. At Salt Lake, the PM2.5 sub-index rose from 117 at 4 pm on Saturday to 330 by 11 pm, before reaching 336 at 1 am. Ballygunge recorded an increase from 148 at 4 pm to 321 at 11 pm, while Jadavpur rose from 159 to 326 during the same period.
Other parts of the city also recorded substantial increases. Fort William’s PM2.5 sub-index rose from 120 at 4 pm to 268 at 1 am. Rabindra Bharati University on BT Road recorded a reading of 265, while Victoria Memorial, which had registered 104 during the afternoon, reached 233 by 3 am. Although pollution began declining before dawn at several stations, readings remained elevated at 5 am, indicating that the pollutant load had not fully dispersed.
PM2.5 was the main concern. These particles can penetrate deep into the lungs, and some can enter the bloodstream. The report said environmentalists also raised concerns about toxic substances associated with firecracker emissions, including heavy metals and combustion by-products. Children, older people and residents with respiratory illnesses face particular exposure risks during such pollution spikes.
Environmentalists attributed the deterioration to the continued use of illegal and non-green fireworks, as well as weak enforcement. Activist Subhas Datta said violations reflected both a lack of civic responsibility and administrative failure. Somendranath Ghosh warned that the effects of cracker pollution could continue after the celebrations because falling night-time temperatures and atmospheric temperature inversions may trap pollutants close to the ground.
Naba Dutta of Sabuj Mancha questioned the sale of illegal crackers in local markets. He said the West Bengal Pollution Control Board had told housing complexes that crackers sold in designated Bazi Bazaars were the only legal ones, but claimed that illegal fireworks were still widely available across the city.
Activists said restricting green crackers to the prescribed two-hour window would have limited impact unless authorities also acted against illegal sales and unauthorised bursting. The reported readings place enforcement, market surveillance and the management of festival-related pollution at the centre of Kolkata’s immediate air-quality response.
