Delhi Weather: Dense fog over Delhi and neighbouring areas has delayed several flights. (File)
Flights were delayed at the Delhi international airport as thick blanket of fog covered the city and its neighbouring areas on Monday morning, reducing the visibility to "zero" in many places.
It is the first time this winter season that visibility in Delhi - infamous for its deadly smog that routinely affects air traffic - has dropped to "zero" in the city. Delhi is likely to witness "moderate" fog on Tuesday as well, he said.
Many major airlines, including IndiGo, SpiceJet and Vistara, took to Twitter to share weather-related travel advisories and urged passengers to check the status of their flights, which may get affected because of low visibility.
SpiceJet also shared similar flight advisories for many other cities in north India - Patna, Darbhanga, Varanasi, Jalandhar and Gorakhpur - where low temperature and changing wind direction affected visibility.
"Delhi's Palam weather station - close to the airport - recorded 'zero' visibility due to 'very dense' fog at 6:30 am," said Kuldeep Srivastava, the head of the regional forecasting centre of the India Meteorological Department.
The visibility should be around 800 metres at the airport for flights to take off, the senior scientist said.
For the rest of the city, "moderate" fog - lowering visibility to 300 metres - was recorded at the Safdarjung Observatory, he said.
Delhi is likely to witness "moderate" fog on Tuesday as well, Mr Srivastava said, adding that this was due to the changing temperature and wind pattern in north India.
The city's night temperature, which was 12 degrees Celsius, is also likely to fall further. This will also affect the quality of air which was "very poor" on Monday. In neigh bouring cities of the national capital region air quality remained in the "severe" category.
(With inputs from Agencies)