New Delhi witnessed another day of severe air pollution on Sunday. This came just one day after authorities implemented Stage-IV measures under the Graded Response Action Plan.
AQI Readings Paint a Grim Picture
The capital's air quality index reached 440 at 4 PM on Sunday. This reading serves as the standard daily measurement. It showed a slight increase from the 428 recorded at 8 PM on Saturday. Both figures fall firmly within the severe category.
This 440 AQI marks the highest January reading since January 14, 2024, when the index hit 447. It also ties for the joint-worst record for the second half of January. A similar reading of 440 occurred on January 17, 2019, according to data from the Central Pollution Control Board.
Notably, all previous peak January readings happened in the first half of the month. This includes the all-time high of 460 recorded on January 15, 2021. Last year, Delhi did not experience a single severe air day in January.
A Significant and Concerning Spike
Sunday's severe air day is the first for Delhi this year. It is also the first since December 29, 2025, when the AQI was 401. This makes it the second-worst air quality day of the current winter season. The worst was December 14, with a peak of 461.
What Caused the Pollution Surge?
Meteorological conditions played a major role. Calm winds associated with a western disturbance, combined with dense fog, trapped pollutants close to the ground. However, experts emphasize that high emissions were a critical factor.
The Centre's Decision Support System provided a breakdown of pollution sources. Delhi's own transport sector contributed the most at 12.5%. Neighboring districts also added significantly to the capital's toxic air. Gautam Budh Nagar contributed 12%, followed by Ghaziabad at 9.4% and Bulandshahr at 8.34%.
Expert Analysis on the Crisis
Sunil Dahiya, founder of think tank Envirocatalysts, explained the perfect storm of conditions. "Low wind speed, stable atmospheric conditions, and the stagnation of local emissions created a buildup," he said. "A higher contribution from neighboring districts to the east and south-west resulted in this sharp spike."
He called for urgent action. "An intervention to reduce emissions at major sources, alongside other GRAP measures in Delhi-NCR, may help reduce the severity. However, long-term relief requires systematic emission reductions across the larger airshed."
Anumita Roychowdhury of the Centre for Science and Environment highlighted the seasonal challenge. "This time of year intensifies adverse atmospheric conditions, trapping already high pollutant levels," she noted. "We've also had a long dry spell. The only solution to mitigate this air emergency is to reduce pollution year-round."
Fog Disrupts Visibility and Travel
Dense fog blanketed the city, reducing visibility to zero in many areas. At Safdarjung, the city's base weather station, visibility remained low between 2:30 AM and 8:30 AM. At Palam, it dropped to just 100 meters at 7:30 AM, according to the India Meteorological Department.
The IMD issued a yellow alert, forecasting moderate to dense fog for Monday morning. While no flights were cancelled or diverted at Indira Gandhi International Airport, travel was significantly delayed. Data from FlightRadar24 showed over 500 flights were delayed, with an average delay of about 34 minutes.
Weather Forecast and Temperature Trends
Sunday's minimum temperature settled at 5.3 degrees Celsius, two degrees below normal. It was 0.9 degrees higher than Saturday's low. As cold wave conditions ease, the minimum temperature is predicted to rise to between 9°C and 11°C by January 23.
The maximum temperature on Sunday was 22.7°C, three notches above normal. It is likely to stay between 24°C and 26°C on Monday. A Met official also indicated the city might receive very light rain on January 23 due to a fresh western disturbance.
Looking Ahead: A Slight Improvement Expected
There is some hope for relief. The Centre's Air Quality Early Warning System predicts the air will improve to the 'very poor' category on Monday. It is expected to remain within that range on Tuesday. While this is an improvement, it still signifies unhealthy air conditions for the city's residents.
