Delhi remained enveloped in a thick haze on Saturday, with air quality hovering on the brink of the “severe” category even as the city experienced its first cold wave of the season and recorded its coldest December day this year.
At 4 pm, Delhi’s 24-hour average Air Quality Index (AQI) stood at 398, just two points short of the severe threshold, while hourly readings from the CPCB’s SAMEER app showed a further deterioration in the evening, with AQI slipping into the severe category at 401 at 5 pm. Several monitoring stations across the city recorded air quality in the severe range.
Out of the 40 monitoring stations in Delhi, 22 reported AQI in the severe category, while 17 stations logged ‘very poor’ levels. Chandni Chowk recorded the worst air quality, with an AQI of 464, falling in the ‘severe plus’ category. The sun remained largely obscured by thick cloud cover and suspended pollutants, significantly reducing visibility across the capital.
Amid prevailing cold-wave conditions, the city’s average AQI deteriorated to 398 on Saturday, compared to 374 on Friday and 373 on Thursday, according to official data.
As per the Central Pollution Control Board (CPCB) classification, an AQI between 0 and 50 is considered ‘good’, 51–100 ‘satisfactory’, 101–200 ‘moderate’, 201–300 ‘poor’, 301–400 ‘very poor’, and 401–500 ‘severe’.
Data from the Decision Support System for Air Quality Management showed that vehicular emissions were the largest contributor to pollution, accounting for up to 17.5%, followed by industries in and around Delhi-NCR at 8.9%. Residential sources contributed 4.3%, while open biomass burning accounted for 1.5%.
Among NCR districts, Jhajjar recorded the highest contribution at 16.5%, followed by Rohtak (around 4.38%), Bhiwani (4.2%), and Gurugram (2.1%).
The Air Quality Early Warning System has forecast that air quality in Delhi is likely to remain in the severe category on Sunday and Monday, before improving marginally to the ‘very poor’ category on Tuesday. The forecast attributes the deterioration to unfavourable meteorological conditions, with the ventilation index remaining below 6,000 square metres per second and average wind speeds below 10 kmph, conditions that are not conducive to the dispersion of pollutants.
Several parts of the city were enveloped in dense smog during the early morning hours, resulting in poor visibility, as earlier forecast by the India Meteorological Department (IMD).
Meanwhile, Delhi experienced its first cold wave day of the season on Saturday. The maximum temperature at Safdarjung, the city’s base station, dropped to 16.9 degrees Celsius, 5.3 degrees below normal, marking the coldest December day this year. At Palam, the maximum temperature settled at 16.3 degrees Celsius, 5.6 degrees below normal.
According to the IMD, Delhi met the ‘cold wave day’ criteria for the first time this winter, with two of its five monitoring stations, Safdarjung and Palam, recording cold wave conditions. The weather department declares a cold wave when the negative departure from the normal maximum temperature ranges between 4.5 and 6.4 degrees Celsius.
For comparison, the lowest maximum temperatures recorded in December in previous years were 14.6 degrees Celsius in 2024, 15.9 degrees in 2023, and 15.6 degrees in 2022, IMD data showed. The minimum temperature on Saturday was recorded at 6.1 degrees Celsius, two notches below normal.
Visibility remained severely affected in the morning hours. At 8.30 am, visibility at Safdarjung dropped to 200 metres, while Palam recorded 350 metres. Conditions improved slightly by 12.30 pm, with visibility increasing to 400 metres at Safdarjung and 600 metres at Palam. Shallow to moderate fog persisted over most parts of the city through the day, with visibility ranging between 400 and 600 metres till afternoon.
The IMD has predicted dense to very dense fog on Sunday and issued an orange alert for the national capital. The maximum and minimum temperatures are expected to hover around 23 degrees Celsius and 9 degrees Celsius, respectively.
In view of the worsening air quality, authorities have stepped up pollution control measures. A ban on the entry of non-Delhi private vehicles that do not meet BS-VI emission standards came into force on Thursday. Enforcement of the ‘No PUC, No Fuel’ rule has also begun, with petrol pumps barred from dispensing fuel to vehicles without valid Pollution Under Control (PUC) certificates.
The enforcement is being carried out using automatic number plate recognition (ANPR) cameras, voice alerts at fuel stations, and police support, officials said.
With air quality remaining close to the severe category, Environment Minister Manjinder Singh Sirsa said on Saturday that strict action would be taken against polluting industries and those violating the construction ban in the capital. He said GRAP-4 restrictions were currently in force across Delhi.
Citing the IMD forecast, Sirsa said a western disturbance was likely to affect Delhi on Sunday, potentially leading to further deterioration in air quality. He added that authorities were receiving multiple complaints about construction activities continuing despite the ban and warned that strict punitive action would be taken against violators.
Directing all industries to strictly adhere to pollution control norms, the minister said no polluting unit should function during the enforcement period. He warned that any industry found operating illegally or contributing to pollution would be sealed.
Sirsa also appealed to citizens and builders to halt all construction activities during the ban period, stating that district administrations had been instructed to take firm action on the ground to ensure compliance.
(With inputs from PTI)