Delhi Chokes On ‘Very Poor’ Air For Fourth Day, AQI Forecast Warns Of ‘Severe’ Levels

Delhi's air quality remained in the ‘very poor’ category for the fourth consecutive day on Thursday, with pollution levels expected to enter the ‘severe’ category from Friday, according to official forecasts. The 24-hour average Air Quality Index (AQI) stood at 369 at 4 pm on Thursday, with 18 of the city's 59 active monitoring stations recording severe air quality. The deterioration comes days ahead of Diwali, when firecracker emissions could add to the city's existing pollution burden. Delhi's average AQI rose to 385 at 5 am on Friday.

According to the Central Pollution Control Board (CPCB), Thursday's average AQI was marginally lower than Wednesday's reading of 377. However, it remained higher than the readings of 350 on Tuesday and 324 on Monday. Of the 59 active monitoring stations in Delhi, 18 recorded ‘severe’ air quality at 4 pm on Thursday. Jahangirpuri reported the highest AQI at 454. By 10 pm, the number of monitoring stations recording severe air quality had risen to 22, according to Hindustan Times.

The AQI scale classifies readings between 301 and 400 as ‘very poor’, while readings between 401 and 500 fall in the ‘severe’ category. The latter indicates emergency-level pollution, with health warnings suggesting that the entire population is more likely to be affected.

Delhi AQI Forecast Warns Of Severe Pollution Until November 8

The Air Quality Early Warning System (AQEWS), developed by the Indian Institute of Tropical Meteorology (IITM), has forecast that Delhi's air quality could remain in the ‘severe’ to ‘very poor’ categories over the next six days.

"The outlook for the subsequent six days is that the air quality is likely to be in severe to very poor category," the AQEWS bulletin said. Its forecast indicated that pollution levels could remain in the ‘severe’ category from November 6 to November 8.

Monitoring station readings also showed the extent of pollution across the capital. Data from the IITM's Air Quality Early Warning and Decision Support System recorded an AQI of 459 in Jahangirpuri, 451 at Delhi Technological University (DTU), 429 in Alipur and 424 in Bawana at 3 am on Friday.

The forecast also points to changing weather conditions affecting the dispersal of pollutants. The AQEWS said the ventilation index over Delhi was expected to fall to 2,500 square metres per second on November 8. A ventilation index below 6,000 square metres per second, combined with average wind speeds below 10 kmph, is considered unfavourable for the dispersal of pollutants.

Stubble Burning And Vehicular Emissions Add To Pollution

The contribution of different pollution sources is also expected to change over the coming days. According to the Ministry of Earth Sciences' Decision Support System (DSS) for Air Quality Management in Delhi, stubble burning accounted for an estimated 15.6 per cent of the city's PM2.5 pollution on Thursday. Its contribution is projected to rise to 19.2 per cent on Friday before dropping sharply to 1.6 per cent on Saturday.

Transport emissions, meanwhile, are expected to account for a larger share of Delhi's PM2.5 pollution. The DSS estimated the transport sector's contribution at 17.9 per cent on Thursday, with the figure projected to rise to 18.3 per cent on Friday and 21.1 per cent by Saturday.

According to The Tribune, Sunil Dahiya, founder and lead analyst at Envirocatalysts, said a western disturbance could weaken north-westerly winds and bring a shift towards easterly winds around Diwali. He said slower winds and morning haze could trap emissions from vehicles, industries, waste burning and firecrackers, adding to the pollution burden.