Delhi Air Quality Improves to AQI 71, but Cleaner Air May Not Last as Rain Activity Changes

New Delhi: Delhi's air quality has improved sharply over the past few days, with the city's average Air Quality Index (AQI) falling to 71 on Friday, bringing pollution levels into the satisfactory category. However, the improvement could prove temporary as rainfall patterns change and the monsoon activity begins to ease.

Data from the Central Pollution Control Board (CPCB) showed Delhi's daily average AQI at 113 on September 1, which fell to 85 on September 2 and 74 on September 3. It improved further to 71 on September 4.

Under the CPCB's classification, an AQI between 51 and 100 is considered satisfactory, while 101-200 falls under the moderate category.

Why has Delhi's air improved?

The recent improvement has largely been linked to stronger winds, which have helped disperse pollutants that had accumulated in the atmosphere.

Ashwary Tiwari, founder of Indiametsky Weather, said pollutants had remained concentrated in the air for several days, contributing to hazy conditions. The increase in wind speed helped disperse those pollutants, while rainfall also played a role in improving air quality.

Rain can temporarily improve air quality by removing some particulate matter from the atmosphere. Strong winds can also prevent pollutants from remaining concentrated over the city.

Clean air may not last

Despite the encouraging AQI reading, experts have warned Delhi residents not to assume that the improvement will continue uninterrupted.

Tiwari said the city's AQI is likely to fluctuate in the coming days as rainfall activity changes. If rain subsides, pollution levels could begin to rise again.

According to the weather expert, AQI levels are expected to continue responding to changes in rainfall throughout September. With relatively limited rainfall forecast for the month, the annual high-pollution period could begin towards the end of September.

That would mark the beginning of the period when Delhi's air quality traditionally becomes a major concern, particularly as weather conditions increasingly favour the accumulation of pollutants.

Heavy rain hits Delhi even as AQI improves

The improved air quality comes on the same day that heavy rain lashed Delhi, causing waterlogging and disrupting normal life across several parts of the capital.

The India Meteorological Department issued a red alert for Delhi on Friday, warning of intense rainfall, thunderstorms, lightning and gusty winds. The heavy weather also disrupted flight operations at Indira Gandhi International Airport, with nine flights diverted.

The IMD has issued a yellow alert for Saturday, forecasting one or two spells of light to moderate rain and thunderstorms. No warning has been issued for Delhi from September 6 onward in the latest seven-day warning.

AQI could become increasingly weather-dependent

Delhi's recent AQI trend highlights how strongly pollution levels can respond to weather conditions.

The fall from 113 to 71 in just three days reflects the impact that wind and rainfall can have on the concentration of pollutants. But if rainfall decreases and atmospheric conditions become more stagnant, pollution could begin building up again.

For residents, particularly those sensitive to air pollution, the current satisfactory levels offer some relief. However, the forecast suggests that air quality may remain variable rather than following a sustained downward trend.

September could mark a turning point

The coming weeks will be important for Delhi's air quality. Experts expect pollution levels to fluctuate with rainfall during September, while the city's yearly high-AQI period could begin towards the end of the month if rain remains limited.

For now, Delhi has a brief spell of comparatively cleaner air. But with the monsoon's behaviour changing, AQI 71 may be a temporary reprieve rather than the start of a lasting improvement.