PIC: DEBAJYOTI CHAKRABORTY
According to West Bengal Pollution Control Board, this is mainly due to change in weather conditions with the onset of winter. The worst-affected areas were Rabindra Bharati University in north Kolkata (AQI 257) and Ghusuri in Howrah (AQI 241). The air pollution level was above 250 in several areas on Wednesday too. Howrah district in West Bengal, specially Howrah city, is thickly populated and predominantly an industrial belt. The spurt in air quality index during this time of the year is a recurring phenomenon this time of the year.