Delhi's Air Quality Index deteriorated slightly early Sunday, January 4, while remaining in the 'poor' category. The AQI recorded around 8 am on Sunday was 298, as compared to 267 recorded around 4 pm on Saturday.
The System of Air Quality and Weather Forecasting and Research (SAFAR) forecast that Delhi's AQI is likely to reach near 390, approaching the 'severe' category, later in the day.
According to the Central Pollution Control Board (CPCB), 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'.
The Air Quality Early Warning System predicted that the AQI is likely to remain in the 'very poor' category from Sunday to January 6, with a similar forecast for the subsequent six days.
Cold wave alert
The India Meteorological Department (IMD) predicted moderate to dense fog in parts of Delhi NCR on Sunday, issuing a yellow alert in most regions.
The IMD also said that cold wave conditions are very likely in isolated pockets of Punjab, Haryana, Chandigarh, and Delhi until January 7.
"Moderate fog at many places with dense fog at isolated places during morning hours," the IMD said, adding that the maximum and minimum temperatures in Delhi are likely to be in the ranges of 17°C to 19°C and 6°C to 8°C, respectively.
"The minimum temperature will be near normal, and the maximum temperatures will be above normal (0.3°C to 2.3°C) over Delhi," the IMD said.
Cold waves are also likely to continue in Rajasthan during January 5 and 8, and over east Rajasthan during January 4 and 8, 2026.
A cold wave is declared when the minimum temperature drops 4.5 to 6.5 degrees below the seasonal average.
On Saturday, the national capital recorded a minimum temperature of 8.1 degrees Celsius, 1.2 notches above the season's average, according to the IMD.
Safdarjung had recorded a minimum temperature of 8.1 degrees Celsius; Palam 7.9 degrees Celsius, 0.9 notches above the seasonal average; Lodhi Road 8 degrees Celsius, two notches above normal; the Ridge 9 degrees Celsius, 1.3 notches above normal; and Ayanagar 6.9 degrees Celsius, 0.1 notches below normal, the IMD data showed.
Meanwhile, Republic Day rehearsals continued at India Gate, with security personnel and parade participants carrying on preparations for the upcoming national celebrations. A layer of smog was visible in the area, reducing visibility, even as rehearsals proceeded as scheduled.
