Orange alert as fog, bad air to smother Delhi’s weekend
The IMD issued an orange alert for fog on Saturday and the AQEWS predicted the air quality index to climb into the 400+ “severe” category over the weekend
Dense fog converged with air pollution to smother Delhi for yet another day on Friday, disrupting over 700 flights and leading to the cancellation of at least 177 more, with worse weather expected over the weekend.
The India Meteorological Department (IMD) issued an orange alert for fog on Saturday and the Air Quality Early Warning System (AQEWS) predicted the air quality index — which barely budged from 373 to 374 in the 24 hours ended at Friday on 4pm — to climb into the 400+ “severe” category over the weekend.
“Dense to very dense fog is expected to form at several places across the city in the early hours of Saturday. At night, a shallow fog or mist might be observed,” an IMD official said, adding that Sunday and Monday would likely see moderate fog at many places and dense fog at isolated locations during morning hours.
On Friday, visibility dropped to zero at the Safdarjung weather station at 5.30am and plunged to 50 metres at Palam, forcing the India Meteorological Department to issue a red alert in the early hours. The disruption left 177 flights cancelled — 88 departures and 89 arrivals, including two international flights — according to airport officials.
While the city’s 24-hour average air quality index stood at 374 in the “very poor” category, the morning reading climbed to 382, edging closer to the severe threshold of 401, while 11 of 40 monitoring stations recorded severe air quality.
Vivek Vihar reported the worst air quality at an index of 434, followed by Anand Vihar at 430. At one point during the day, 14 stations were in the severe category before conditions improved slightly at some locations.
The deteriorating air marked the ninth consecutive day of very poor or severe pollution despite an aggressive vehicular enforcement drive launched Thursday that resulted in thousands of challans and widespread disruption to those using their own vehicles across NCR— underscoring what the Supreme Court described earlier this week as the “total failure” of reactive pollution control measures.
The minimum temperature was recorded at 9 degrees Celsius on Friday, 0.9 degrees above normal, while the maximum reached 22.2 degrees. Forecasts suggest the minimum could fall to 7-9 degrees on Saturday, with the maximum hovering around 21-23 degrees over the weekend before dropping to 20-22 degrees by mid-next week.
The temperature decline threatens to intensify what meteorologists call the inversion effect, trapping pollutants in lower layers of the atmosphere. “A fall in temperature can intensify the inversion effect, which can lead to a spike in pollution levels, as this causes pollutants to get trapped near the lower layers of the atmosphere,” said Anumita Roychowdhury, executive director at the Centre for Science and Environment. “However, the intensity of the spike will depend on several meteorological conditions, including wind speed, and the interplay between the meteorological conditions.”
Data from the Centre’s Decision Support System for Air Quality Management showed vehicular pollution contributed 15.72 percent to Friday’s pollution despite Thursday’s enforcement drive targeting older vehicles and those without valid pollution certificates. Forecasts indicate this contribution will rise to 17.36 percent on Saturday and 18.41 percent on Sunday, even as restrictions remain in effect.
December has already recorded three severe air days between Dec. 13-15, with the month’s average air quality index climbing to problematic levels. The capital experienced a 24-day streak of very poor air between Nov 6 and 29, including three severe days from Nov. 11-13. HT reported on Friday that this December, till now, has been the dirtiest in eight years.
The Supreme Court, in a sharp assessment on Wednesday, directed the Commission for Air Quality Management to abandon short-term responses in favour of comprehensive structural reforms addressing urban mobility, industrial emissions and agricultural burning. The court emphasized that sustainable solutions require coordinated action across Delhi, Uttar Pradesh, Haryana and Rajasthan, and scheduled its next hearing for Jan. 6.
The persistent fog also highlights the absence of rainfall this December, with the Safdarjung weather station recording no precipitation, including trace amounts. The lack of rain prevents pollutants from being washed out of the atmosphere, compounding the air quality crisis.
