India, Sept. 28 -- 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.

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 Sc...