Delhi records cleanest August air since 2020 amid wet spell

Delhi rains

Delhi woke up to light showers on Sunday, which once again helped the city breathe cleaner air. The Capital’s air quality remained in the “satisfactory” category, with the Central Pollution Control Board (CPCB) recording a 24-hour average Air Quality Index (AQI) of 91. This was an improvement from Saturday’s reading of 118, which fell under the “moderate” category, Hindustan Times reported.

According to CPCB data, the national capital has been witnessing a trend of improved air quality this year, with frequent rainfall and strong winds that wash away pollutants. As of August 17, Delhi has recorded 53 days of “satisfactory” air quality in 2025, the highest number in the same period since 2020.

In 2024, Delhi had only 37 such days during this time and none in the “good” category (AQI of 50 or below). The Capital saw 46 “satisfactory” days in 2023, 44 in 2022, 36 in 2021, 76 in 2020, and fewer than 30 in the years before that. The year 2016 had just 14 days of clean air by this time.

Experts believe this year’s relatively cleaner air is mainly due to early and consistent rainfall that began in May.

“The cleaner air this year, compared to previous years, is largely due to the early onset of rains from May, which helped wash down pollutants. While meteorological factors have been the primary driver for more days of better air quality, minor contributions may also come from improved fuel standards, a growing fleet of BS-VI and electric vehicles, and possibly reduced construction activity,” HT quoted Sunil Dahiya, founder and lead analyst at think-tank Envirocatalysts, as saying.

Delhi also came very close to recording a “good” air day last month, with the AQI dipping to 51 on July 15. The city has not had a “good” day between January and mid-August since 2020, when Covid-19 lockdowns temporarily halted most pollution-causing activities.

Another positive sign this year is that Delhi has not reported a single “severe” air quality day so far, which means the AQI has not crossed 400 even once. The last time Delhi saw no severe days during this period was in 2017. In comparison, Delhi had three “severe” days each in 2023 and 2024, one in 2022, six in 2021, and several in earlier years.

Weather experts say the pattern is linked to a very active monsoon. Mahesh Palawat, vice president at Skymet, noted that Delhi has been receiving ample rainfall almost every month since May, with several spells of excess rain. “Frequent rain ensures that pollutants and dust do not stay in the air for long,” he was quoted by HT as saying.

August has already seen 257.7 mm of rainfall, which is above the monthly average of 233.1 mm. May was the wettest ever on record with 186.4 mm of rain, six times the normal average. June saw 45 per cent excess rain, while July also recorded 24 per cent above-normal rainfall.