Dense fog enveloped the national capital on Friday morning as cold day conditions prevailed, the Met office said.
According to the India Meteorological Department (IMD), the minimum temperature at Safdarjung was recorded at 9.1 degrees Celsius. Other stations logged similar readings, with Palam and Lodhi Road recording a minimum of 9 degrees Celsius each, Ridge 8.7 degrees Celsius, and Ayanagar 8.1 degrees Celsius.
The weather office said a cold wave was likely to affect isolated places between January 2 and January 5.
A cold wave is declared when the minimum temperature drops 4.5 degrees Celsius to 6.5 degrees Celsius below the normal average temperature, it said. Cold day conditions are declared when the maximum temperature falls 4.5 notches below normal, he added.
The weather office further said dense to very dense fog is likely to continue during the night and morning hours at many places in Delhi. The maximum temperature is likely to settle around 18 degrees Celsius.
Meanwhile, air quality in the national capital remained in the ‘very poor’ category, though it showed marginal improvement. The Air Quality Index (AQI) was recorded at 302 in the morning.
According to CPCB classification, an AQI between 0 and 50 is considered 'good', 51 to 100 'satisfactory', 101 to 200 'moderate', 201 to 300 'poor', 301 to 400 'very poor', and 401 to 500 'severe'.
Data from the Central Pollution Control Board's SAMEER app showed that 19 monitoring stations were in the 'very poor' category, 15 in 'poor', and one in 'severe', with NSIT Dwarka recording the poorest air quality at 423. On Thursday, the 24-hour average AQI stood at 380.
The Air Quality Early Warning System has forecast that air quality is likely to remain in the 'very poor' category till January 4, with similar conditions expected over the following six days.