Days after Diwali and Kali puja, the air quality in the city remained in the moderate category with environmentalists blaming the unregulated use of firecrackers behind the rise in the pollution level.

At 10 am on Wednesday, the AQI (PM2.5) at Victoria Memorial and Fort William was 134 and 109, respectively. Similarly, at Jadavpur and Ballygunge, it was 108 and 104, respectively. The AQI level at Bidhannagar was 109, according to the National Air Quality Index by the Central Pollution Control Board, Ministry of Environment, Forests and Climate Change.

At 6 pm on Sunday, when the city was celebrating Diwali, the AQI was over 250 in Ballygunje, Jadavpur, Fort William, and Victoria Memorial, which is referred to as poor air quality.

At 10 am on Monday, a day after the celebrations, AQI reading was 284 at Victoria Memorial, 262 at Fort William, 254 at Jadavpur, 234 at Rabindra Sarobar and 236 at Salt Lake. An AQI between 0 and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”, officials said.

Speaking to The Indian Express, environmentalist Naba Dutta said the relentless use of firecrackers and relaxation in the decibel limits are the reasons behind the rise in air and noise pollution levels. “This was evident as there was no check on the use of firecrackers, especially the ones which do not fall under the green firecracker category. The firecrackers which failed the QR code test were sold in the market. These firecrackers pollute the air more than green firecrackers. Therefore, the relentless use of firecrackers is the prime reason why the AQI is not coming down to a satisfactory level,” Dutta said.