Kolkata: Kolkata’s air quality index (AQI), which improved to good (AQI: 0-50) on Monday, again swung back to the ‘satisfactory’ (AQI: 51-100) level, with the wintry chill setting in, lowering the vertical wind speed. Thanks to the influence of cyclonic Midhili in the Bay of Bengal which swerved towards Bangladesh, the post-Diwali ambient air of the city improved dramatically.
From Friday evening, the air quality moved to ‘good’ category for the first time in November, staying throughout Saturday. But from Sunday morning, it swung back to satisfactory AQI. In the coming days, thanks to meteorological conditions, the air quality might decline further. The fireworks revelry by Chhath devotees will have an impact on the air quality, said environment activist Somendra Mohan Ghosh.