The meteorological parameters of the MeT has predicted, “Moderate, shallow and dense fog till December 31. The wind speed was recorded at 14 km per hour at 7 pm.”

While explaining fog conditions in Delhi, Dr Rajendra Jenamani an expert of the India Meteorological Department (IMD) said fog layer covered the city throughout the day with visibility level reduced to 200-300m between 9:30 and 11:30 am, an unusual timing. “Due to wind reversal from easterly to westerly at 9 am, there was intensification of fog at Delhi,” said the MeT expert.

“As there was no sun light, the maximum temperature was restricted to 15-16 degrees Celsius while it was 24-25 degrees Celsius on Saturday,” said Dr Jenamani.

Citing the reason for deteriorating air quality, environmentalist Gopal Krishna said when a layer of warm air settles over a layer of cooler air that lies near the ground, the warm air holds down the cool air and prevents pollutants from rising and scattering.

“And to overcome the process of pollutants’ immobility, the Government institutions have to take strict action on pollution contributors by cracking down on movement of heavy vehicles in the city. Also, industrial operations should be stopped during the dense fog period and people should be encouraged to use public transportation,” said Krishna.

Meanwhile, the values of prominent particles (Particulate Matter (PM) 10, 2.5) at Anand Vihar Air quality Index (AQI) were recorded at 508 and 339 (In Micro cubic per gram).

At Mandir Marg area, the concentration were recorded at 404 and 281 while in RK Puram area, values of both pollutants were 404,345 and 448, 251respectively.

A level of Carcinogenic Element (CE) Benzene has been recorded 19.1micro cubic per gram which is the highest in December this year. Importantly, the prescribed standard of Benzene at NAQI is 5 µg/m3.

While marking the Delay Index (DI) as Orange, the flight federation of US has recorded 2.25 per cent delay rate at Indira Gandhi International Airport (IGIA).

“The sky will remain clear throughout the day. Mist or shallow fog is likely to occur in the morning on Monday,” the IMD official tweeted, adding that the visibility would be between 500 metres to 600 metres.

Meanwhile, railway officials said 80 Delhi-bound trains were running behind schedule by several hours, while 23 others required to be rescheduled owing to poor visibility. However, there was no fresh cancellation of services announced. “The 34 services, which were announced as cancelled between the period December 17 and January 15, said a Northern Railway official.