Rains bring cleanest air of the year to Delhi. AQI at 52 amid September showers

Delhi’s air quality got an unexpected breather on Friday, with the capital recording its cleanest air in a year, thanks to persistent rains. The city’s air quality index (AQI) dropped to 52, placing it in the ‘satisfactory’ category—a rare occurrence in a year plagued by fluctuating pollution levels. But the relief may be short-lived, as forecasts predict a deterioration by Sunday and Monday.
This brief improvement underscores a growing concern: Delhi’s air pollution problem is no longer confined to the winter months. Over the summer, the city’s AQI frequently swung between the ‘moderate’ and ‘poor’ categories, signalling an extended period of compromised air quality.
According to the Central Pollution Control Board (CPCB), Delhi’s AQI touched 49 at 3pm on Friday, briefly entering the ‘good’ category. However, the 24-hour average AQI remained slightly higher at 52 by 4pm. By Saturday morning, the AQI rose slightly to 53. The last time Delhi enjoyed air this clean was on 10 September 2023, when the AQI hit 45.
Continuous downpours have been key to this improvement. Between Friday morning and early Saturday, Palam recorded 70 mm of rain, while Safdarjung saw 60 mm. The deluge helped clear the air, washing pollutants out of the atmosphere and contributing to the best air quality in months.
Delhi’s monsoon season has already surpassed its average rainfall, with 616.1 mm recorded so far, compared to the normal 510 mm. September alone has seen 125.8 mm of rain, 55% above average, further aiding the temporary respite from pollution.
The heavy rains on Friday not only cleared the air but also caused a significant drop in temperatures, with the maximum in Delhi falling to 27.6 degrees Celsius—six degrees below the seasonal average. The India Meteorological Department (IMD) forecasts that, as the downpours subside, the minimum temperature will likely hover around 21 degrees Celsius on Saturday, while the maximum is expected to settle around 32 degrees Celsius.
However, forecasts from IMD suggest that while air quality remains in the ‘satisfactory’ range today, conditions are expected to worsen into the ‘moderate’ category by the end of the weekend. Above-normal rainfall has been recorded across the country, with northwest India experiencing heavy showers, and Delhi has benefited from this surge.