New Delhi: The air quality in Delhi deteriorated sharply after Diwali 2025, recording the worst pollution levels in nearly five years, despite a major reduction in stubble burning incidents across Punjab and Haryana.
According to the Central Pollution Control Board (CPCB), Delhi’s 24-hour average Air Quality Index (AQI) on October 21–22 remained in the “very poor” to “severe” category, ranging between 345 and 353. However, IQAir, a Swiss-based global air-quality platform, reported real-time AQI readings exceeding 650 in several city locations, briefly ranking Delhi among the most polluted cities in the world.
Experts explained that the differences arise from distinct measurement methods. The CPCB calculates AQI based on 24-hour averages from official monitoring stations, while IQAir uses instantaneous real-time data, which often captures short-term pollution peaks.
Despite a 77% decline in stubble burning in neighbouring states, Delhi’s air quality worsened sharply after Diwali night.
Reports by LiveMint and India Today attribute this spike primarily to:
Extensive firecracker use during Diwali celebrations.
Vehicular emissions and construction dust.
Low wind speed (below 1 m/s) and temperature inversion, which trapped pollutants close to the surface.
According to CPCB and SAFAR-India data, PM₂.₅ concentrations crossed 480 µg/m³, over eight times the safe limit prescribed by the World Health Organization (WHO).
(PM2.5 refers to airborne particles less than 2.5 microns wide that can penetrate deep into the lungs and bloodstream, posing serious health risks.)
Data from the Indian Agricultural Research Institute (IARI) and Punjab Remote Sensing Centre confirmed that farm fire incidents in Punjab and Haryana dropped by more than three-fourths compared to last year. Experts noted that flooding during the harvest season delayed paddy cutting, which led to fewer stubble-burning events.
Satellite-based assessments showed that stubble smoke contributed less than 10% to Delhi’s PM₂.₅ levels during the Diwali period, compared with 30–40% in previous years.
Meteorological factors significantly contributed to the smog build-up.
Wind speeds fell below 1 m/s, reducing the dispersion of pollutants, while a temperature inversion trapped smoke and dust close to the surface. The night-time temperature dropped from 27 °C to 19 °C, worsening stagnation.
Satellite images and ground sensors captured a dense haze layer persisting from October 21 to 23. Visibility across several parts of Delhi dropped below 800 meters on Monday morning.
PM₂.₅ particles are fine inhalable pollutants smaller than 2.5 microns that can penetrate deep into the lungs and enter the bloodstream. Doctors from Delhi’s leading hospitals, including AIIMS and LNJP, cautioned that short-term exposure to high PM₂.₅ levels can trigger:
Asthma attacks, bronchitis, and eye irritation.
Worsening of heart and lung diseases in vulnerable individuals.
Increased risk of stroke and cardiac events.
Health experts advised residents to avoid outdoor physical activity, wear N95 or KN95 masks, use air purifiers indoors, and seek medical care if experiencing breathing discomfort or chest pain.
The Commission for Air Quality Management (CAQM) invoked Stage II of the Graded Response Action Plan (GRAP) in Delhi-NCR ahead of Diwali. The measures included:
Ban on construction and demolition activities.
Restriction on diesel generator use (except for essential services).
Prohibition on coal and firewood in restaurants.
Intensified mechanized road cleaning and water sprinkling.
Officials noted that while these interventions reduce background pollution, they cannot fully offset sudden emission surges caused by fireworks.
Apart from Delhi, several other major Indian cities experienced elevated pollution levels after Diwali 2025. Mumbai recorded AQI values as high as 341 in Colaba, placing it in the “very poor” category, while Kolkata saw readings above 350 in areas such as Dum Dum and Park Circus. Patna also fell into the “poor” category.
Experts attributed these spikes to firecracker use and local emissions, compounded by stagnant air and low wind speeds. Meteorologists forecast gradual improvement as wind speeds rise and air circulation resumes mid-week.
By October 23, Delhi’s air quality remained in the “very poor” category across most monitoring stations, with localities such as Anand Vihar, RK Puram, and Jahangirpuri recording AQI values above 370. The IMD forecast predicted gradual improvement over the next few days if wind speeds increased, though pollution is expected to remain high as winter approaches.
(Rh/Eth/MSM)
