Delhi’s air quality to remain ‘very poor’ until week’s end: Experts

Pollution levels in the national capital remained in the “very poor” category for the third consecutive day on Wednesday, with the city recording a marginal rise in its air quality index (AQI) compared to Tuesday’s readings.

Delhi’s air quality dipped to “very poor” on Diwali day, registering an AQI of 345, which further declined to 351 on Tuesday and 353 on Wednesday, according to data from the Central Pollution Control Board (CPCB).

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The hourly PM2.5 levels in parts of Delhi spiked to over 29 times the national permissible limit of 60 micrograms per cubic meter (µg/m³) on Diwali night, following the widespread bursting of crackers across the city.

The capital’s overall average PM2.5 concentration peaked at 675 µg/m³ at midnight on Diwali — the highest since 2021, when the average had touched 728 µg/m³ on the festival day.

Despite the sharp increase in PM2.5 values on Monday, the city’s air showed gradual improvement thereafter. Experts attributed the decline to favourable meteorological conditions, which helped disperse firecracker emissions.

Above-normal temperatures were also recorded on Wednesday, with the minimum settling at 21.8°C — 3.6°C above normal. The mercury had soared to 32.9°C a day earlier, and the weather department has forecast similar temperature ranges for both minimum and maximum levels until the weekend.

In the past 24 hours, Delhi experienced consistent easterly to south-easterly winds of up to 10 kmph since Tuesday morning, helping to dissipate pollutants accumulated after Diwali.

According to the Centre’s Decision Support System, the contribution of stubble burning to Delhi’s PM2.5 levels remained low on Diwali (0.8%) and the following day (1%), due to the predominant easterly wind direction. On Wednesday, the contribution saw a slight uptick, rising to 1.625%.

The Early Warning System forecasts that Delhi’s AQI is likely to stay in the “very poor” category until at least Friday. Over the subsequent six days, the air quality is expected to fluctuate between “poor” and “very poor,” the statement said.