With visibility of just 50m in some areas, Delhi Airport took to Twitter to alert passengers that flights not equipped to operate in such conditions “may get affected.”

Local media reported that 15 trains to Delhi were also running late due to fog.

The India Meteorological Department (IMD) said in a bulletin that “dense and very dense fog” was likely to continue over some parts of the city over the next 24 hours due to light wind and high moisture levels.

“Its intensity and spread (is) likely to reduce thereafter,” the IMD said.

The IMD also forecast cold wave conditions in some areas over the northwest states of Punjab, Haryana, and Delhi during the next two days.

A cold wave is declared in the plains of India when the minimum temperature dips to 4°C – or falls 4.5°C below normal to 10°C or below.