Delhi AQI update: Capital chokes on 'very poor' air with worst October reading in 3 years

Delhi pollution

Delhi’s air quality deteriorated sharply this week, hitting its worst level for October in three years before a slight, tentative improvement, as stalled cloud seeding efforts underscored the challenges in tackling the annual crisis.

On Thursday, the national capital’s average Air Quality Index (AQI) soared to 373, plunging into the ‘very poor’ category and marking the highest reading for the month since October 2022. Data from the Central Pollution Control Board’s (CPCB) Sameer app showed the city was enveloped in a thick haze, severely reducing visibility.

The reprieve, when it came, was modest. By Friday morning, the average AQI had improved to 288, categorised as ‘poor’. However, the CPCB data revealed a patchy recovery, with monitoring stations at Anand Vihar and Bawana still registering AQIs of 305 and 363 respectively, solidly in the ‘very poor’ range.

The dramatic dip on Thursday was driven by a combination of adverse meteorological conditions. The India Meteorological Department (IMD) reported that calm south-easterly winds, high humidity levels around 90% and a significant drop in night temperature created a ‘temperature inversion’. This phenomenon, where a layer of warm air traps cooler air and pollutants near the ground, severely limited the atmosphere's ability to disperse harmful particles.

Compounding the problem, Thursday’s maximum temperature was recorded at 27 degrees Celsius, the lowest for October in two years. The Air Quality Early Warning System noted that the city’s ventilation index — a measure of the air's dispersive capacity — remained unfavourably low.

Amid the worsening conditions, a planned technological intervention has been put on hold. The IIM-Kanpur confirmed that the next trials for cloud seeding, a technique intended to induce artificial rain and wash away pollutants, have been suspended. The reason cited was “insufficient moisture in the clouds”.

Delhi’s Environment Minister, Manjinder Singh Sirsa, elaborated on the setback. He stated that an initial trial conducted on Tuesday with 10-15% moisture had not yielded the desired results. “The next trial will be held when the moisture exceeds that level,” he told ANI on Wednesday, adding that further attempts would depend on updated IMD forecasts.

The situation quickly attracted political criticism. Aam Aadmi Party convener and former Delhi chief minister Arvind Kejriwal quoted a media report questioning the success of the cloud seeding trial on X, writing, “Actually, all the engines of this government have failed. This government itself has completely failed.”

Data from the Decision Support System highlighted the sources of the pollution, indicating that while the contribution from stubble burning remained modest at 2.57%, vehicular emissions accounted for nearly 16.7% of the capital's PM2.5 levels as of Wednesday.

The forecast from the Indian Institute of Tropical Meteorology offers little immediate hope, predicting that air quality is expected to remain in the ‘very poor’ range for the next several days as light winds and stable atmospheric conditions persist.