New Delhi is experiencing a significant decline in air quality, as weak winds are trapping pollutants and causing hazardous conditions across the city and surrounding National Capital Region (NCR). On Sunday, the city's overall Air Quality Index (AQI) reached 366, placing it in the "very poor" category, according to the Central Pollution Control Board (CPCB). Several monitoring stations have recorded AQI levels above 400, which is classified as "severe".
The primary pollutants of concern are PM2.5 and PM10. PM2.5 refers to fine inhalable particles with diameters of 2.5 micrometers or smaller, while PM10 includes slightly larger particles up to 10 micrometers in diameter. On Sunday, the PM2.5 concentration stood at 189.6 micrograms per cubic meter, and PM10 was recorded at 316. These pollutants at such high levels can cause breathing discomfort, especially for vulnerable populations such as children, the elderly, and those with heart or lung conditions.
The Air Quality Early Warning System (AQEWS) for Delhi has indicated that the wind speed has dropped below 8 kmph from the northwest, particularly during the evening and night, which is reducing the dispersion of pollutants. A ventilation index lower than 6,000 m²/s and wind speeds less than 10 kmph are considered unfavorable for pollutant dispersal. The AQEWS has warned that the air quality is likely to remain in the "very poor" category until November 4.
The deterioration in air quality is also affecting neighboring cities within the NCR. Ghaziabad (351), Gurugram (357), Noida (348), and Greater Noida (340) have all reported "very poor" air quality. Faridabad, however, recorded a "poor" AQI of 215. Haryana's Dharuhera recorded an AQI of 434, falling in the "severe" category.
Visibility has also been affected by the dense smog, with the Safdarjung weather station reporting visibility at 900 meters and Palam at around 1,300 meters. The India Meteorological Department (IMD) noted light winds at around 4 kmph, which are insufficient to disperse pollutants. The maximum temperature was 30.5°C, nearly three degrees below normal, and the minimum temperature was 19.4°C, slightly above normal. Humidity stood at 73% on Saturday evening, further contributing to smog formation.
Experts have cautioned that pollution levels may continue to rise if weather patterns do not change. Stubble burning in neighboring states and local emissions are also contributing to the pollution. Without strong northwesterly winds or rainfall, Delhi's air quality is expected to remain poor in the coming days.
