LUCKNOW, Aug. 27 -- The city, over the past few weeks, has breathed air cleaner than even several hill stations in the country, thanks to the frequent monsoon showers.

Out of the 26 days of August till Tuesday, Lucknow witnessed 10 'good' and 16 'satisfactory' days as the air quality index (AQI) was recorded below 90 on all of these days, Central Pollution Control Board data suggested.

CPCB defines AQI between 0 and 50 as 'good' and 51 and 100 as satisfactory.

On Tuesday, the city's AQI dropped to 48, indicating that the air quality was cleaner than in Kohima (68), Rajgir (84), and Ooty (50).

"Monsoon is the biggest purifier," said JP Maurya, the regional officer of UP Pollution Control Board. "Rainfall brings PM2.5 and PM10 dust part...