Lucknow: Done with Diwali, air quality takes a turn for 'severe'

Lucknow: Diwali celebrations had a ruinous impact on the air quality in city, dragging it down into the 'severe' category. Despite Supreme Court order and increased awareness about air pollution, the air quality deteriorated by 62% compared to last Diwali.
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With rise in pollution, the city's Air Quality Index (AQI) shot up to 412 on Thursday, the highest post-monsoon so far. The AQI was 255 on Diwali in 2017 while it was even higher at 422 on the day in 2016.

As per the data released by Central Pollution Control Board (CPCB), the average 24-hour PM 2.5 concentration monitored from 4pm on Diwali (November 7) till 4pm next day was 412, around seven times higher than the permissible limit as per National Ambient Air Quality Standards.

According to environmental scientists and weather experts, along with bursting of crackers, drop in the minimum temperature and very low wind velocity also contributed to increasing the pollution level.

"Bursting of crackers was no doubt the main reason behind the 'severe' air quality but low temperature and less wind velocity further elevated the pollution level by not allowing the particulate matter to disperse," said Lucknow University climate and air quality monitoring station director Prof Dhruv Sen Singh.

The minimum temperature on November 7 was 11.2 degree Celsius which further dropped to 10.2 degree Celsius, preventing the warm and heavy polluted air from rising up that would have improved air quality. Low wind velocity also made things difficult as the pollutants stagnated in the air and formed a thick layer in the lower atmosphere.

After recording high pollution level of 348 on October 25, the city witnessed improvement in air quality in November. The AQI on November 5 was 266 but it started increasing thereafter till the spike on Diwali. On Friday, the AQI was 377, which still falls in the 'severe' category.