New Delhi is grappling with severely degraded air quality three days after Diwali, with multiple areas recording hazardous Air Quality Index (AQI) levels. The city's air pollution has soared to alarming levels, despite restrictions on firecrackers.
On Tuesday, two days after Diwali, the city was blanketed in a dense layer of smog. The Central Pollution Control Board (CPCB) recorded a 24-hour average AQI of 345, categorizing the air quality as "very poor". Some areas experienced even worse conditions, with early morning readings around 380 in Ashok Vihar, Bawana, and Dilshad Garden. On Wednesday, the city-wide AQI averaged 451 at 7 am. Satellite cities including Noida and Gurgaon reported AQI readings of 407 and 402 respectively.
According to Swiss air quality firm IQAir, the city's AQI reached 442 on Tuesday morning, making it the most polluted major city in the world. Some parts of Delhi showed an AQI of more than 500, exceeding the World Health Organization's (WHO) guidelines by ten times. In certain areas, the levels of PM2.5 and PM10, dangerous toxic particles, peaked at 1,800, which is 15 to 20 times higher than the levels considered healthy.
The surge in pollution is attributed to the widespread use of fireworks during Diwali celebrations, combined with cooler months when traffic, industry, and agriculture emissions are trapped. A recent report indicates that post-Diwali PM2.5 levels reached 488 µg/m³, a 212% increase from pre-Diwali levels. The concentration of PM2.5 in the city's air on Tuesday morning was more than 59 times the WHO's recommended annual guideline.
Calm winds and a drop in temperature have exacerbated the problem, preventing the dispersion of pollutants and trapping them in the atmosphere. The Ministry of Earth Sciences anticipates that the air quality will remain "Very Poor to Poor," with AQI levels between 201 and 400 in the coming days.
The severe air quality poses significant health risks, particularly for vulnerable groups. Residents have reported experiencing breathing difficulties and eye irritation. Exposure to such high levels of pollution can lead to neurological, cardiovascular, and respiratory diseases, and increase the risk of cancer.
Authorities have implemented Stage II of the Graded Response Action Plan (GRAP) across Delhi-NCR in response to the deteriorating air quality. In the past, authorities have closed schools, stopped construction work and placed restrictions on private vehicles to try to tackle the problem. The Supreme Court had allowed the sale and bursting of green firecrackers in Delhi-NCR between 6 am and 7 pm, and again from 8 pm to 10 pm on Diwali eve and the festival day.
Despite a reported 77% reduction in farm fires in Punjab and Haryana, Delhi's air quality has turned more toxic after Diwali 2025. Climate Trends' analysis of Central Pollution Control Board (CPCB) data from 2021 to 2025 reveals that Delhi's air pollution levels during Diwali 2025 surged to dangerous highs, with PM 2.5 concentrations averaging 488 µg/m³ post-Diwali. This indicates that firecracker emissions are a significant contributor to Delhi's air pollution, overshadowing any reductions achieved from decreased stubble burning.
