On Saturday, Delhi’s air was the cleanest it has been all year with an Air Quality Index (AQI) of 58. With the rainfall this month, the AQI has remained in the ‘satisfactory’ category for 24 out of 30 days of the month till Saturday. AQI between 51 and 100 is considered ‘satisfactory’ by the Central Pollution Control Board (CPCB). The average AQI in July this year was 87, better than the 110 recorded in 2021. July this year and July of 2020 have seen the cleanest air in the past six years. In 2020, July saw an average AQI of 83, only a little better than the average for the month this year. Air quality in July this year fared better than the AQI in July 2019 and 2018. In 2019, the average AQI for the month was 134, while it was 103 in 2018. There were also fewer 'satisfactory' air quality days in 2021, 2019, 2018 and 2017. The cleaner air this month comes after a string of 'poor' and 'very poor' air quality days in June, when dust and little rainfall kept the AQI in the higher ranges. Monsoon hit Delhi on June 30 this year, bringing 'satisfactory' air quality days to the city from early July onwards. The Safdarjung weather observatory has recorded excess rainfall of 35% this July — 273.4 mm against a normal of 201.9 mm. The monsoon hit Delhi a little later last year, on July 13, while the onset date was earlier in 2020 on June 25. There have been no 'good' air quality days so far this year in Delhi. As of July this year, the AQI has either remained in the 'moderate' or 'satisfactory' categories, but has not deteriorated to reach the 'poor' or 'very poor' categories.
