Dense Fog Grounds Over 100 Flights, Halts 50 Trains as Delhi on Orange Alert

A combination of dense fog and hazardous air pollution continued to grip the national capital on Friday, severely disrupting air and rail services and pushing air quality closer to the “severe” category, with conditions likely to worsen over the weekend.

More than 700 flights were impacted during the day, while at least 177 flights and 50 trains were cancelled as visibility dropped sharply across the city. Of the cancelled flights, 88 were departures and 89 arrivals, including two international services, airport officials said.

The India Meteorological Department (IMD) issued an orange alert for fog for Saturday, warning of dense to very dense fog during early morning hours. The Air Quality Early Warning System also forecast the Air Quality Index (AQI) to cross the 400 mark, placing Delhi in the “severe” category over the weekend.

“Dense to very dense fog is likely at several places during the early hours of Saturday. Shallow fog or mist may also occur during night hours,” an IMD official said, adding that moderate fog is expected on Sunday and Monday, with dense fog in isolated pockets during mornings.

On Friday morning, visibility dropped to zero at Safdarjung at 5.30 am and fell to 50 metres at Palam, prompting the IMD to issue a red alert in the early hours.

Delhi’s 24-hour average AQI stood at 374, firmly in the “very poor” category, while morning readings climbed to 382, nearing the severe threshold of 401. Eleven of the city’s 40 air quality monitoring stations recorded “severe” levels during the day.

Vivek Vihar reported the worst air quality with an AQI of 434, followed by Anand Vihar at 430. At one point, 14 stations slipped into the severe category before marginal improvement was observed later in the day.

Friday marked the ninth consecutive day of very poor or severe air quality in the capital, despite intensified vehicular enforcement measures launched a day earlier. Thousands of challans were issued across the NCR, disrupting private transport and underscoring what the Supreme Court recently described as a “total failure” of reactive pollution control measures.

The minimum temperature on Friday settled at 9°C, nearly one degree above normal, while the maximum reached 22.2°C. Forecasts suggest minimum temperatures could drop to 7–9°C on Saturday, with daytime highs between 21–23°C over the weekend, followed by further cooling next week.

Meteorologists warned that falling temperatures could intensify inversion conditions, trapping pollutants closer to the surface.

“A drop in temperature strengthens inversion conditions, preventing pollutants from dispersing,” said Anumita Roychowdhury, executive director at the Centre for Science and Environment, adding that pollution levels would depend on wind speed and other meteorological factors.

According to the Centre’s Decision Support System, vehicular emissions accounted for 15.72% of Friday’s pollution load. This share is expected to rise to 17.36% on Saturday and 18.41% on Sunday, despite restrictions on older vehicles and those without valid pollution certificates.

December has already recorded three severe air days between December 13 and 15, making it the dirtiest December in eight years so far. In November, Delhi experienced a 24-day stretch of very poor air quality, including three severe days.

Earlier this week, the Supreme Court directed the Commission for Air Quality Management to move beyond short-term emergency measures and focus on long-term structural reforms such as urban mobility, industrial emissions and stubble burning, stressing coordinated action across Delhi, Uttar Pradesh, Haryana and Rajasthan. The matter will be heard again on January 6.

The crisis has been exacerbated by the absence of rainfall this month, with Safdarjung recording zero precipitation in December, preventing the natural dispersal of pollutants.

Meanwhile, Delhi Airport issued a passenger advisory stating that low-visibility procedures remain in place. “All flight operations are functioning normally. Passengers are advised to contact their respective airlines for the latest flight updates,” the advisory said.