Delhi air on verge of ‘severe’ again, 27 flights cancelled

With the India Meteorological Department (IMD) issuing a yellow fog alert for Friday, the operations may continue to remain affected, experts said

New Delhi

The Delhi-Gurgaon Expressway on Thursday morning. (Parveen Kumar/HT Photo)

The Capital continued to be blanketed in fog on Thursday due to dipping air quality, which plummeted from the lower-end of “very poor” to around 373 by the afternoon, forcing the cancellation of at least 27 flights and delaying the operation of 500 more, hindering operations for a fourth consecutive day, officials aware of the matter said.

Delhi had recorded an AQI of 334 the day before. By 9pm on Thursday, the AQI reached 397, moving closer to the “severe” category by the hour. With the India Meteorological Department (IMD) issuing a yellow fog alert for Friday, the situation may worsen, experts said.

With the India Meteorological Department (IMD) issuing a yellow fog alert for Friday, the operations may continue to remain affected, experts said. To be sure, the IMD had only forecast shallow to moderate fog on Thursday.

“Delhi’s air quality is likely be in the ‘very poor’ category from December 19 till December 29. The AQI is likely to be in the ‘severe’ category on December 21. The outlook for the subsequent six days from December 22 also shows that the air quality is likely to be between ‘severe’ and ‘very poor’,” said the Centre’s Air Quality Early Warning System for Delhi (EWS) on Thursday.

Experts said a feeble western disturbance exists currently in the form of a weak cyclonic circulation, which brought moisture to the northern plains.

“Winds were also slow, allowing fog formation. A marginal increase in wind speed is likely on Friday. However, another weak western disturbance is expected over the weekend, which will again slow down wind speed. We can again expect a deterioration in AQI between December 20 and 22,” said Mahesh Palawat, vice president at Skymet, a private forecaster.

Visibility drops

The visibility dipped to 100 metres in the Capital on the day, impacting both railway and flight operations.

“At 2.30am, visibility at Safdarjung was 300 metres and it was 500 metres at Palam. Visibility continued to dip and was 150 metres at Palam and 200 metres at Safdarjung at 6am – further dipping to 100 metres at both stations at around 6.30am,” an IMD official said.

Experts said that low winds, high moisture content in the air and high pollution levels created a thick smog, which kept a continuous haze through the day.

“Flights were impacted, but this was not only down to low visibility here but also across the northern region. Visibility was zero at multiple other airports and so there has been an effect of flights being delayed at other airports too. Some flights were cancelled in advance too,” an airport official, requesting anonymity, said.

Data from flight tracking website Flightradar24 showed that over 500 flights stood delayed, while airport officials confirmed at least 27 flights were cancelled. This included 16 departures and 11 arrivals, including flights to Chandigarh and Lucknow, which recorded zero visibility. Officials said visibility dipped to zero at the Hindon airport, Agra airport, Kanpur airport, and Gorakhpur airport.

On Monday, the city’s first very dense fog day of the season, over 800 flights were delayed, over 200 cancelled and five had to be diverted due to bad weather as visibility plummeted to zero at Delhi’s base station at Safdarjung and to 50 metres at the Palam observatory.

The IMD classifies fog as “shallow” when visibility is between 500 and 1000 metres, as “moderate” when visibility is between 200-500 metres, as “dense” when it is between 50 and 200 metres, and as “very dense” when it falls to below 50 metres.

The Directorate General of Civil Aviation (DGCA) norms allow aircraft to land with visibility of 50 metres, but require a minimum visibility of 125 metres for take-offs.

In a post on X on Thursday morning, The Delhi airport warned of disruptions due to dense fog. “Due to dense fog, flight operations are currently under CAT-3 conditions, which may lead to delays or disruptions. We are working closely with all stakeholders to minimise inconvenience to passengers,” said the post at 8.10am.

Frustrated passengers took to social media to vent their anger.

Passenger Lipika Dey was scheduled to travel on AI 1743, from Delhi to Chandigarh, but it was cancelled. “No apologies, no reasons - just a message cancelled! Who compensates for our work? I had to cancel the return flight and cab. Lost money…(sic),” she said.

In a response, Air India said the flight was cancelled due to bad weather in Delhi.

Gaurav Singh, whose Delhi-Lucknow flight scheduled for 6am was cancelled on Thursday, said he received the message for cancellation at around 2am. “There is a high court date in the morning. If the court issues any against order then will Air India be responsible..” Singh questioned.

Air India responded, stating the flight – AI2499 had been cancelled due to the “consequential impact of poor visibility caused by dense fog in Delhi.”

Northern Railways officials said that at least 25 trains were delayed under the Delhi division. “The delay ranged from 30 minutes to 7 hours,” an official said.