Delhi records 15-week high AQI. What changed the capital's air?

Earlier, Delhi recorded an AQI of 187 on June 13 and slid to further moderate levels in the subsequent days owing to heavy rains and strong winds.

After enjoying a rather long streak of clean air days, Delhi on Saturday clocked an Air Quality Index of 169, a 15-week high. Earlier, the national capital recorded an AQI of 187 on June 13 and slid to further moderate levels in the subsequent days owing to heavy rains and strong winds.

According to Central Pollution Control Board (CPCB), Delhi recorded the cleanest average AQI since 2016 in the first half of this year.(RAJ K RAJ /HT PHOTO)

While the AQI improved at 155 by 11pm, experts suggest that such fluctuations in this season are normal.

“Fluctuations like this in this season are normal. We see a lot of variation in the meteorological conditions post-monsoon, before the cold weather conditions start to set in. These meteorological conditions, in turn, can cause fluctuations like this and cause a sudden spike in pollution level.” Anumita Roychowdhury of Centre for Science and Environment said.

Vice president of Skymet, Mahesh Palawat attributed the spike in Saturday's AQI to the change in the wind direction. “There was a change in wind direction from the dry westerlies to more humid easterlies. As a result, the humidity pulled in dust and smoke, thus increasing the pollution level. In the evening, however, the speed of the winds increased, slightly improving the AQI," he said.

A bench of Chief Justice of India BR Gavai, Justices K Vinod Chandran and NV Anjaria permitted the certified manufacturers of green crackers, who have the permits from the NEERI and the PESO, to manufacture green crackers in Delhi-NCR, subject to the condition that they will not be sold in the National Capital Region.