A haze engulfed Kolkata and its neighbourhood on Sunday, the day of Diwali and Kali Puja in West Bengal, as the air quality remained poor with the bursting of firecrackers, state pollution control board officials said.

The AQI was over 250 in Ballygunje, Jadavpur, Fort William, Victoria Memorial in the city and in Ghusuri in neighbouring Howrah district at 6 pm on Sunday, and such readings on automated monitoring stations refer to poor air quality, they said.

The control room at Paribesh Bhavan, headquarters of the West Bengal Pollution Control Board (WBPCB), is functioning, while drone surveillance and mobile teams are also in operation at various hotspots in the city and adjacent areas, one of the officials said.

"So far we have not come across any incident about bursting of illegal firecrackers exceeding sound levels of 125 decibels,” he said.

As per the reading of air monitoring stations, the air quality index (AQI) was 216 (PM 2.5) at Rabindra Sarobar, 257 at Ballygunje, 276 at Victoria Memorial, 267 at Jadavpur, 255 at Fort William, 243 at Bidhannagar, 183 at Rabindra Bharati University and 262 at Ghusuri at 6 pm, the official said.

All readings were classified as "poor", he said.

Such a situation was not only caused by the bursting of firecrackers but also weather conditions during this time of year when small particulate matters remain in the air with the presence of fog and smoke, the official said.

On the previous day, the AQI at Ballygunge, Victoria Memorial and Bidhan Nagar was 300 (very poor). In Rabindra Sarobar, it was 243 (poor), while Jadavpur and Fort William recorded 268 (poor), as per the PCB readings.

An AQI between zero 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'.

Environmentalist Naba Dutta said the pollution level shot up after sunset as celebrations with fireworks began in different parts of the city. "If the pollution level aggravates, it will cause respiratory problems," he said.

Another green activist Somendra Mohan Ghosh said, "We recommend sprinkling water on plants in the evening to reduce the effect of pollution apart from regular police patrolling in areas like Jadavpur, Tollygunje, Kasba, Behala, Beleghata, Entally, Chitpur, Cossipore, Dumdum, Lake Town of the city.

“If the bursting of crackers continues in late evening hours, it will aggravate the air quality situation,” Ghosh said.

Meanwhile, a survey by an NGO, SwitchON Foundation, in two green firecracker markets at Sahid Minar and Tala Park in Kolkata, and some local vendors in Bhawanipur, found that despite the administration's regulations and penalties for illegal fireworks activities, the lack of public awareness about green crackers during Diwali remains a significant issue.

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