Dense fog delays over 150 flights as Delhi’s air quality remains ‘very poor’

The flight tracking website Flightradar24 showed that over 150 flights were delayed at the Delhi airport between midnight and 8am

Published on: Dec 30, 2025, 09:17:59 IST

By Jasjeev Gandhiok

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Dense fog enveloped Delhi on Tuesday, delaying over 150 flights, even as the air quality improved marginally and was in the higher end of the “very poor” category. The visibility dropped to 100 metres at Palam by 10:30pm on Monday, and remained 50 metres until 5:30am on Tuesday. At Safdarjung, visibility fell to 50 around midnight and remained in this range until around 8am. At 8:30am, it improved to 200 metres.

A yellow alert is in place for New Year’s Eve for moderate to dense fog. (HT PHOTO)

Fog is classified as shallow when visibility is between 500 and 1000 metres, moderate between 200 and 500 metres, dense between 50 and 200 metres, and very dense when it dips below 50 metres.

A red alert was issued around 10:30pm for Delhi as visibility dipped to 100 metres at Palam. A yellow alert is in place for New Year’s Eve for moderate to dense fog.

The flight tracking website Flightradar24 showed that over 150 flights were delayed between midnight and 8am. On Monday, over 550 flights were delayed, 130 cancelled, and eight diverted. Northern Railways said some trains were running late on Tuesday morning.

A 24-hour rolling average air quality Index (AQI) of 388 (very poor) was recorded at 8am on Tuesday, compared to 401 (severe) at 4pm on Monday, the fifth such day this month and the eighth overall this year.

December is on track to be the most polluted since 2018, with the average monthly AQI of 349 until December 29, the highest since it was 360 seven years back.

ABOUT THE AUTHOR
Jasjeev Gandhiok
Jasjeev Gandhiok is an Assistant Editor with Hindustan Times, where he covers environment, climate change, the clean energy transition and wildlife at the National Bureau. Gandhiok has over a decade of experience in journalism and is based in Delhi. He has reported extensively on Delhi and the National Capital Region (NCR). This includes the region's air pollution woes, a polluted Yamuna and on urban wildlife still thriving in the region. He joined HT in October 2021. Prior to that, he had five-year stint at The Times of India in Delhi, where he also covered Delhi, with a focus on environment and wildlife. Gandhiok has covered some recent events around the Capital too, ranging from the farmers' protests, the northeast Delhi riots and the CAA-NRC protests, reporting from the ground on all of these. He also travels across the country to report on how environment and climate change impact everyday life, while also writing on endangered species. His reports in 2019 on toxic leachate from Delhi's landfills led to the National Green Tribunal (NGT) taking suo motu cognisance and ultimately asking the state government to start bio-mining to flatten and remove all three landfills in the capital. He also closely tracks the implementation of government policies on climate, renewable energy and environmental protection. His focus remains on impactful, public-interest journalism which explains how environmental decisions affect people's everyday lives.Read More

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