A thick blanket of dense fog covered large parts of north India on Friday morning, severely impacting the visibility. The India Meteorological Department (IMD) issued a red alert for Delhi, warning of major disruptions to road, rail and air traffic.

Satellite imagery showed widespread fog over Punjab, Haryana, Delhi, Uttar Pradesh, northeast Madhya Pradesh and Bihar.

Visibility dropped to zero metres at several locations, including Agra, Bareilly, Saharanpur and Gorakhpur in Uttar Pradesh; Amritsar, Ludhiana, Bathinda and Adampur in Punjab; Safdarjung in Delhi; Gwalior in Madhya Pradesh; Bhagalpur in Bihar; and Daltonganj in Jharkhand.

The IMD cautioned that extremely poor visibility could impact airport operations and cause delays on highways and railway routes.

An orange alert was issued for multiple districts in Uttar Pradesh, parts of Uttarakhand, Haridwar and Udham Singh Nagar, and several districts in Punjab, including Amritsar, Patiala and Sangrur.

Meteorologists warned of hazardous driving conditions and an increased risk of road accidents, along with the possibility of power line tripping in affected regions. Residents were advised to avoid unnecessary travel, use fog lights, and stay updated on transport advisories.

According to IMD definitions, “very dense fog” occurs when visibility ranges between 0 and 50 metres, while “dense fog” refers to visibility between 51 and 200 metres.

In Delhi, early morning visibility remained poor due to dense fog mixed with smog.

Delhi’s air quality remained alarming, with the 24-hour average Air Quality Index (AQI) recorded at 382, placing it in the ‘very poor’ category and close to ‘severe’.

Data from the Central Pollution Control Board showed that 14 monitoring stations reported ‘severe’ air quality, while the remaining recorded ‘very poor’ levels. Vivek Vihar registered the worst AQI at 434.

The Air Quality Early Warning System for Delhi has forecast that air quality will stay ‘very poor’ until Saturday and may deteriorate to ‘severe’ on Sunday.

Meanwhile, stricter pollution control measures came into effect in the national capital on Thursday. The entry of non-Delhi private vehicles below BS-VI emission standards has been banned, and the ‘No PUC, No Fuel’ rule is being enforced.

Fuel stations are denying fuel to vehicles without valid Pollution Under Control certificates, with checks supported by automatic number plate reader cameras, voice alerts and police deployment.