Other stations in the city were colder, with 3°C logged at Palam and 3.7°C at Ridge. According to the India Meteorological Department (IMD), Sunday was the coldest January morning in Palam in the last 13 years, since the station recorded 2.6°C on January 7, 2013.

As per forecast, “coldwave” will continue in the national Capital till Wednesday. IMD has issued an orange alert for “coldwave” in the city for Monday and Tuesday and yellow alert for Wednesday. “It is expected at many places on Monday and Tuesday and in isolated pockets on Wednesday,” an IMD official said.

“Coldwave conditions were witnessed over Delhi as Palam, Ridge and Ayanagar reported minimum temperatures less than 4.1°C. No respite from the chills is expected in the coming days,” IMD scientist Krishna Mishra said.

The IMD classifies it as a “coldwave” if the minimum temperature on a day is below 10°C while its departure is also 4.5°C or more below the season’s normal. Alternatively, it is also classified as a “coldwave” if the actual temperature at stations in the plains falls below 4°C.

The minimum temperature is expected to be between 2-4°C on Monday and around 3-5°C on Tuesday and Wednesday.

Delhi recorded the maximum temperature at 18.8°C on Sunday, which was a degree below the season’s normal. It was 20.2°C on Saturday. While sunshine is expected during the day on Monday, icy-cold winds will likely continue, keeping the maximum between 18-20°C on Monday and 19-21°C on Tuesday.

Across the city, shallow to moderate fog was recorded in the early hours. While the lowest visibility in Delhi fell to 200 metres at Palam at around 4am, Safdarjung’s lowest was 600 metres at 6.30am.

Over 300 flights at the Indira Gandhi International (IGI) Airport were delayed on Sunday due to the fog, with no cancellations recorded, as per the flight tracking website FlightRadar24.

AQI “poor” now

Delhi’s air quality on Sunday improved slightly from “very poor” zone to the higher end of “poor”. As the wind speeds picked up on Sunday, the 24-hour average air quality index (AQI) stood at 291 (poor) at 4pm, as against 346 (very poor) at the same time on Saturday, according to the Central Pollution Control Board (CPCB).

Forecasts by Centre’s Air Quality Early Warning System (EWS) for Delhi shows that a deterioration is again expected on Monday.

“The air quality is likely to be in the ‘very poor’ category from January 12 till January 14. The outlook for the subsequent six days – from January 15 shows the air quality is likely to stay in the ‘very poor’ category,” said the EWS in its daily bulletin.

According to CPCB estimates, an AQI reading between 51 to 100 is classified as “satisfactory”, and between 101 and 200 is classified as “moderate”, between 201 and 300 is “poor”, between 301 and 400 is “very poor”, and over 400 is “severe”.