‘Severe’ air quality to persist in North India for next six days amid cold winds and pollution crisis

On November 17, Delhi's Air Quality Index (AQI) reached 441 at 4 pm, indicating 'severe' pollution, and worsened to 457 by 7 pm.

The air quality in North India is expected to remain in the 'severe' or 'severe+' category for the next six days, as unfavourable weather conditions continue to trap pollutants over the region. Strong cold winds sweeping through the plains have worsened the air quality, with pollution levels spiking to the most hazardous this season on Sunday. The Indian Institute of Tropical Meteorology (IITM) has forecasted that the ongoing adverse meteorological conditions, including low wind speeds and poor dispersion, will sustain the high levels of pollution.

On November 17, Delhi's Air Quality Index (AQI) reached 441 at 4 pm, indicating 'severe' pollution, and worsened to 457 by 7 pm. In response, the Commission for Air Quality Management (CAQM) imposed GRAP Stage IV, the highest level of emergency action, aimed at controlling the smog. By 10 pm, all air quality monitoring stations in the city (except for a few stations with unavailable data) reported AQI levels exceeding 400.

The India Meteorological Department (IMD) issued an orange alert for November 18, forecasting dense fog and smog conditions throughout the morning, with temperatures expected to dip gradually over the next five days. Dense fog was already reported at Palam airport by November 17 night, where visibility dropped from 900 meters in the morning to just 150 meters by late evening.

Experts attribute the severe pollution levels to a combination of factors, including jet stream winds of up to 100 knots (185 kmph) over North India, which are contributing to the subsidence of cold air. In addition, the westerlies, with wind speeds of 10-16 kmph, combined with ongoing stubble burning, have significantly increased the concentration of fine particulate matter (PM 2.5). The Central Pollution Control Board (CPCB) recorded PM 2.5 levels crossing 300 micrograms per cubic meter — five times the national air quality standard — for the first time this season.