New Delhi: A thick blanket of smog descended over the national capital on Thursday, triggering widespread health concerns as residents complained of burning eyes, persistent cough, and difficulty in breathing. The city’s air quality plunged close to the “severe” category, marking one of the worst days this season.
According to the Central Pollution Control Board (CPCB), Delhi recorded an overall Air Quality Index (AQI) of 373, up sharply from 279 a day earlier. Out of 38 monitoring stations in the city, 37 reported “very poor” air quality, with areas such as Vivek Vihar (426), Anand Vihar (415), Ashok Vihar (414), Bawana (411), Wazirpur (419), and Sonia Vihar (406) crossing into the “severe” category.
The CPCB said PM2.5 levels, the most harmful pollutant that penetrates deep into the lungs, stood at 184.4 µg/m³, while PM10 levels reached 301.9 µg/m³. Both readings are several times higher than the World Health Organisation’s prescribed safe limits.
Neighbouring cities in the National Capital Region (NCR) also fared poorly. Noida recorded an AQI of 372, Ghaziabad 364, Greater Noida 330, Gurugram 248, and Faridabad 166. Experts say stagnant weather, high humidity, and low wind speeds have trapped pollutants close to the ground, creating the toxic haze that shrouded the skyline.
Experts described the yellowish-grey blanket hanging over the city as smog, a deadly mix of fog and pollutants that reduces visibility and severely affects respiratory health. The India Meteorological Department (IMD) said haze conditions are expected to persist in the early mornings and evenings for the next few days as particulate matter continues to accumulate. “The dip in minimum temperature helps in forming a layer of haze as pollution settles in the lower atmosphere,” said Mahesh Palawat, vice-president of meteorology and climate change at Skymet Weather. “Winds blowing from the east at 2 to 5 kmph and a rise in humidity worsened the air quality on Thursday. Medium and low clouds have obscured the sky, and isolated light rain was recorded in Noida and Faridabad.”
The IMD also recorded visibility levels of 1,000 metres at Palam and 800 metres at Safdarjung around 7:30 a.m., both reporting calm wind conditions.
According to the IMD’s Decision Support System, Delhi’s transport sector contributed 15.9 per cent to the PM2.5 levels, while stubble burning accounted for 6 per cent and local emissions from residents 4 per cent. Neighbouring cities, Ghaziabad and Noida, contributed 10 per cent and 6 per cent, respectively, while other regional sources together added over 22 per cent.
Satellite data for October 29 detected 283 farm fire incidents in Punjab and 10 in Haryana, indicating that stubble burning continues to play a role in the worsening air quality.
Weather experts, however, stressed that while stubble smoke contributes to pollution, it is the meteorological conditions that make the situation so severe.
“The Indo-Gangetic Plain is witnessing low wind speed, which hampers ventilation,” said Dipankar Saha, former additional director and head of the air laboratory at the CPCB. “However, this doesn’t mean emission control can be ignored, reducing emissions will still lessen exposure to harmful pollutants.”
Echoing similar concerns, Sunil Dahiya, founder and lead analyst at Envirocatalyst, said, “Decreasing wind speed and overcast conditions are reducing pollutant dispersion. To see any significant improvement, emission sources across the power, industry, transport, waste and construction sectors in Delhi-NCR need to be targeted.”
The Air Quality Early Warning System for Delhi reported that the city’s ventilation index, a measure of the atmosphere’s ability to disperse pollutants, remained below the favourable level of 6,000 m²/s. Weak winds under 10 kmph and high humidity prevented pollutants from escaping, resulting in the thick haze that blanketed Delhi throughout the day.