New Delhi, Dec 30 (IANS): Delhi and national capital region (NCR) were enveloped in a thick blanket of fog on Monday morning, reducing the visibility and affecting air traffic and vehicular movement.

At least 30 Delhi-bound trains were delayed for one to seven hours due to the low visibility in several parts of northern India.

The minimum temperature recorded at the Safdarjung observatory was 2.6 degrees Celsius), Palam at 2.9 degress Celsius and Lodhi Road 2.2 at degrees Celsius, according to the India Meteorological Department (IMD).

Air quality index (AQI) in the capital on Monday was 449 with particulate matter (PM) 2.5, the Met officials added.

Some of the places in north India that recorded lowest temperatures are Amritsar with 2.8 degrees Celsius, Ambala 4.4 degrees, Rajasthan 2 degrees, Agra in UP 2.4 degrees and Gaya 3.8 degrees.

Dense fog and eventual poor visibility have caused flight delays and cancellations across north India in the past few days. Delhi airport authority had earlier warned that flight departures might impact if visibility falls below 125 metres.