Delhi-NCR chokes under dense fog, flights, trains affected as visibility drops to zero; AQI in 'severe' category

A thick blanket of fog engulfed Delhi and its adjoining NCR cities on Sunday, reducing visibility to near zero as biting cold conditions persisted across the region. The dense fog prompted several airlines, including Air India and IndiGo, to issue advisories, warning passengers to anticipate delays and to check their flight status. According to flight tracking website, Flightradar24, there was a 35% delay in departures and 27% delay in arrivals at the Indira Gandhi International Airport.

The fog also hit dozens of trains, with delays stretching up to 12 hours. Several premium trains, including the Rajdhani, Duronto and Garib Rath Express trains, were among those affected. The railway administration scrambled to manage the situation, but passengers faced significant disruptions.

#WATCH | Delhi | A layer of toxic smog engulfs the national capital. Visuals from the Janpath Road. GRAP 4 invoked in the national capital. pic.twitter.com/wcTzm0T2V3

— ANI (@ANI) January 18, 2026

Train services severely affected

According to the railway administration, among the affected trains are:

12436 Anand Vihar–Jaynagar Garib Rath Express

22362 New Delhi–Rajendra Nagar Amrit Bharat Express

15657 Delhi–Kamakhya Brahmaputra Mail

20802 New Delhi–Islampur Magadh Express

13151 Howrah–Jammu Tawi Kolkata Express

12310 New Delhi–Rajendra Nagar Patna Rajdhani Express

12274 New Delhi–Howrah Duronto Express

13258 Anand Vihar–Danapur Jansadharan Express

19436 Asansol–Ahmedabad Weekly Express

12392 New Delhi–Rajgir Shramjeevi Express

12354 Lal Kuan–Howrah Express

12818 Anand Vihar–Hatia Swarna Jayanti Jharkhand Express

Air quality remains 'severe'

Compounding the situation, the capital continued to choke under severe air pollution, with the Air Quality Index (AQI) touching 439 at 7 am today. In response to the worsening air quality, authorities implemented curbs under GRAP-IV, the strictest anti-pollution measures, on Saturday. The Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) declared a ban on the entry of truck traffic into the city, except for those carrying essential commodities and providing essential services.

GRAP-IV curbs imposed in Delhi

With the air quality in Delhi plummeting to the ‘severe’ category, the CAQM imposed Stage 4 of the Graded Response Action Plan (GRAP), a set of short-term emergency measures taken to combat air pollution.

Delhi on Saturday recorded a minimum temperature of 4.4 degrees Celsius, which was 3.2 notches below the season's average, according to the India Meteorological Department (IMD).

"Minimum temperatures are expected to begin rising gradually from January 17 to 20, with light winter rainfall activity likely over the next few days," said Mahesh Palawat from Skymet Weather, a private weather forecasting agency. He added that another cold spell is forecast between January 23 and 26, when temperatures are expected to dip again.

Schools to work on ‘hybrid mode’

Classes for school students, except for those in Grade 10 and 12, will be shifted to ‘hybrid mode’ in Delhi and in neighbouring districts, including Gurugram, Ghaziabad, Faridabad, and Gautam Budh Nagar. Notably, existing restrictions under GRAP 1, 2, and 3 will continue to remain in force.