Kolkata and Howrah, West Bengal’s two most polluted cities, recorded the cleanest post-Diwali air quality in years. The Air Quality Index (AQI) of the two cities dropped to 37 and 36 on Tuesday morning thanks to the rain and strong winds triggered by cyclone Sitrang on Monday night. According to the Central Pollution Control Board, Kolkata’s AQI was 37 in the good category at 7am on Tuesday. Delhi’s AQI was 326 (very poor), Mumbai’s 193 (moderate) category, and Chennai’s 230 (poor).
Last year, Kolkata’s AQI a day after Diwali was 207 in the poor category. In 2020, it was 187 (moderate), 219 in 2019, and 326 in 2018.
The AQI in Howrah, an industrial city, dropped to 36 on Tuesday morning. In 2021, the AQI of Howrah, a day after Diwali, was 265, and 217 in 2020.
Bibhuti Biswas, 72, a Kolkata resident, said such an air quality after the Kali Puja night is unthinkable. “Usually on Kali Puja night, we have to keep windows closed to avoid smoke and pollution. You get a burning sensation in your eyes and throat. But it was windy and there was some rain flushing out the pollution. We could keep the windows open thanks to the cyclone.”
Cyclone Sitrang made landfall close to Barisal in Bangladesh on Monday night and triggered strong winds and light rain in Kolkata (2.4 mm).
An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 severe.