The air in Delhi on Friday was the cleanest it has been in nearly a year, PTI reported. The monsoon’s arrival in the city and the National Capital Region has not only brought down the temperature but has also reduced pollution.

The Air Quality Index for Delhi on Friday was at a “satisfactory” 72, according to the Central Pollution Control Board. An Air Quality Index reading up to 50 is considered “good” and up to 100 is considered “satisfactory”. A reading between 401 and 500 is ranked “severe” on the index, which means the air is dangerously filled with pollutants.

The prominent pollutants in the air were PM10 particles, the concentration of particulate matter of diameter less than 10 microns, the board said.

The last time the air in the national Capital was this clean was in August 2017, an official of the Central Pollution Control Board told PTI.

“The air quality will further improve tomorrow [Saturday] and in the coming days,” Gufran Beig, a scientist at the Centre-run System of Air Quality and Weather Forecasting and Research institute, said. “The monsoon winds cleaned the dusty air and brought the air quality to satisfactory level.” He added that the air quality may even improve to “good”.

The monsoon arrived in Delhi on Thursday, a day before its predicted date. On Friday, the minimum temperature in the city was around 27 degrees Celsius and the maximum around 36 degrees Celsius, providing immense relief to its residents. The city had reeled under extreme heat conditions this summer, with the maximum temperature touching 45 degrees Celsius.