Firecrackers still Delhi’s top pollutant after Deepavali, IITM finds

A thick layer of smog is seen in New Delhi on November 11, 2026. | Photo Credit: Shashi Shekhar Kashyap

Firecrackers emerged as the biggest contributor to Delhi's air pollution on both Monday (November 9, 2026) and Tuesday (November 10), accounting for 71.1% and 29.8% of the pollution load, respectively, according to source-apportionment estimates by the Indian Institute of Tropical Meteorology (IITM).

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The contribution of firecrackers to the city's pollution levels was significantly higher on Monday (November 9), a day after Deepavali, before declining on Tuesday (November 11), the IITM models showed.

The estimates had a standard deviation (SD) of 104.1 percentage points on Monday (November 9) and 27.7 percentage points on Tuesday (November 10), indicating considerable variability and uncertainty in the modelled contributions.

On Monday (November 9), vehicular emissions accounted for 6.9% of the pollution, followed by secondary inorganic aerosols at 5% and secondary organic aerosols at 4.5%. Mixed or unresolved biofuel contributed 4.45%, while mineral dust and ash and mixed combustion accounted for 2.5% each.

Wood burning contributed 1.3%, while waste burning, including municipal and plastic-rubber-containing waste, accounted for 1.1%. Coal combustion and industrial emissions contributed 0.5% and 0.2%, respectively.

On Tuesday (November 10), the contribution of firecrackers dropped to 29.8%, while secondary organic aerosols emerged as the second-largest contributor at 17.5%.

Vehicular emissions and secondary inorganic aerosols each accounted for 11.7% of the pollution load, while wood burning contributed 10.7% and waste burning 7.7%.

Vehicular emissions emerged as the third largest contributor to pollution on Tuesday (November 10).

Mixed combustion accounted for 5.1%, followed by mixed or unresolved biofuel at 3.3% and mineral dust and ash at 1.5%.

Delhi's average 24-hour Air Quality Index (AQI) had improved marginally to the 'poor' category on Tuesday (November 10), with the 4 p.m. reading settling at 299.

However, air quality deteriorated again on Wednesday (November 11), with the AQI climbing to 312, placing it in the 'very poor' category.

An AQI between 201 and 300 is classified as 'poor', while readings between 301 and 400 fall in the 'very poor' category.

The IITM estimates indicate that while the contribution of firecrackers declined after Deepavali, they continued to remain the single largest identified source of pollution on Tuesday (November 10).

Published - November 11, 2026 02:35 pm IST