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