Delhi’s air quality plunged to a season-high ‘very poor’ AQI of 388

NEW DELHI: Delhi’s air quality deteriorated sharply on Sunday, reaching a season-high AQI of 388 in the very poor range at 10 am. It marginally improved to 366 by 4 pm.

The improvement was credited to afternoon winds, but forecasts suggest the relief may be short-lived, and Delhi may record its first severe AQI of the season by Tuesday.

The Centre’s Air Quality Early Warning System has said that the AQI is “very likely to remain in the very poor category from Sunday to Monday” and then move to “severe on Tuesday, before returning to very poor readings on Wednesday.” Long-term trends underline that Delhi has entered its most polluted phase of the year. A Delhi Pollution Control Committee (DPCC) analysis of Central Pollution Control Board’s (CPCB) data found that Nov 1–15 has consistently recorded the highest AQI levels annually, followed by Dec 16–31. On Sunday, by 4 pm, five of the 39 active monitoring stations had slipped into the severe zone — Burari (404), Chandni Chowk (404), RK Puram (401), Vivek Vihar (402), and Wazirpur (418). Another 30 were in the very poor range, CPCB data showed.Meteorologists attributed the worsening air to stagnant conditions that trap pollutants close to the surface. “Winds picked up to around 10 km/hr during the day, which briefly improved the air quality,” said Mahesh Palawat, the vice-president (meteorology and climate change) at Skymet. He added that wind direction turned westerly to northwesterly in the afternoon, which can favour the transport of stubble smoke from neighbouring states.A western disturbance is expected in north India between Nov 4 and 5, but Palawat said it is unlikely to bring rainfall. “Delhi will only see some cloudiness,” he said.Data from the Decision Support System (DSS), which identifies pollution sources, showed that transport was the largest contributor to Delhi’s PM2.5 load at 18.1%, followed by emissions from Jhajjar district (11.2%) and Delhi’s residential sector (4.5%). About 36.8% of the particulate matter came from regional sources outside Delhi that are unaccounted for. The contribution from stubble burning stood at 3.5% on Sunday, down from 9% a day earlier. The concentration of PM2.5 was critically high on Sunday. In the morning, several stations such as Anand Vihar, Ashok Vihar, Burari, Narela, Rohini, Vivek Vihar and Wazirpur reported hourly PM2.5 levels between 400 and 459 µg/m³. Citywide, the average hourly PM2.5 peaked at 11 am to 274 µg/m³, with smaller peaks at 7 am (262 µg/m³), 8 am (261 µg/m³), and noon (259 µg/m³). A brief dip was recorded around 4 pm, when it dropped to 95 µg/m³, before rising again. For the 24-hour average, against the national safe limit of 60 µg/m³, several locations recorded hazardous levels. Wazirpur topped with 263.6 µg/m³, followed by Burari Crossing (247.8 µg/m³), Chandni Chowk (241.2 µg/m³), and Anand Vihar (226.8 µg/m³).The minimum temperature was 16.8°C and the maximum 30.7°C, which is close to the seasonal average. The minimum could dip below 15°C after Nov 7, marking the onset of winter.