Firecrackers, vehicle emissions, aerosols among top sources of Delhi pollution, IITM estimates show

Firecrackers were the largest identified contributor to Delhi's air pollution on both Monday and Tuesday after Diwali, accounting for an estimated 71.1% and 29.8% of the pollution load, respectively, according to source-apportionment models developed by the Indian Institute of Tropical Meteorology (IITM). Meanwhile, Chamber of Trade and Industry (CTI) chairman Brijesh Goyal argued that firecrackers were being unfairly blamed for the capital's pollution and called for attention to other sources, including stubble burning.

The IITM estimates showed that the contribution of firecrackers was substantially higher on Monday, a day after Diwali, before declining on Tuesday. Despite the drop, they remained the single largest identified source in the model's estimates for the second day.

The estimates also showed contributions from several other sources, including vehicle emissions, secondary aerosols, wood burning and waste burning.


Also Read: After home guard takes Diwali gift from motorist, Haryana orders bodycams for traffic stops

What were the sources of Delhi's air pollution after Diwali?

The IITM models identified the following sources and their estimated shares in Delhi's pollution load on Monday and Tuesday:

Source of pollution	Monday (%)	Tuesday (%)
Firecrackers	71.1	29.8
Vehicular emissions	6.9	11.7
Secondary inorganic aerosols	5.0	11.7
Secondary organic aerosols	4.5	17.5
Mixed or unresolved biofuel	4.4	3.3
Mineral dust and ash	2.5	1.5
Mixed combustion	2.5	5.1
Wood burning	1.3	10.7
Waste burning	1.1	7.7
Coal combustion	0.5	Not specified
Industrial emissions	0.2	Not specified

Source: IITM source-apportionment estimates. Tuesday figures for coal combustion and industrial emissions were not provided in the available data.

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

On Tuesday, secondary organic aerosols were the second-largest contributor at 17.5%, followed by vehicular emissions and secondary inorganic aerosols, both at 11.7%. Wood burning accounted for 10.7% and waste burning for 7.7%.

Delhi AQI rises from poor to very poor category

Delhi's average 24-hour Air Quality Index (AQI) improved marginally to 299 at 4 pm on Tuesday, placing it in the poor category. However, air quality deteriorated again on Wednesday, with the AQI climbing to 312, entering the very poor category.

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

Also Read: Emergency brakes applied but train not stopping: Video shot by Kolkata-Sairang express driver shot moments before it derails

CTI chairman says firecrackers are being unfairly blamed for pollution

Amid the debate over firecrackers, CTI chairman Brijesh Goyal said sales in Delhi were estimated at around Rs 300 crore during Diwali. He argued that firecrackers were being unfairly singled out for the city's pollution and urged political parties to work together to address stubble burning and other sources of emissions, according to ANI.

Goyal said Delhi remained a major market for firecrackers, with much of the supply coming from Sivakasi and other places. He also maintained that businesses could have managed their sales better if permissions had been granted earlier.

While acknowledging that firecrackers produce smoke, Goyal argued that their impact was temporary. He also pointed out that pollution levels remained high between October and January, even before Diwali, and called for attention to other contributors, particularly stubble burning.

CTI flags impact of firecracker restrictions on traders

The traders' body claimed that around 10 lakh people across the country were associated with the firecracker industry, including manufacturers in Sivakasi and small retailers in Delhi. It said many small traders invested in the business throughout the year and depended on the 15-20 days around Diwali to earn a significant portion of their annual income.

CTI also said traders had invested in licensed stocks and green firecrackers, arguing that last-minute restrictions affected their investments and livelihoods.

As an alternative to a complete ban, the organisation proposed allowing fewer firecrackers, restricting their use to designated timings and promoting green firecrackers. It also raised concerns about the impact of restrictions on children's festival celebrations.

CTI questions restrictions on Hindu festivals in the name of environment

The organisation also objected to what it described as selective restrictions on Hindu festivals in the name of environmental protection. It cited Diwali, Holi, Chhath, Kanwar Yatra and Ganesh visarjan, and called for environmental regulations to be applied equally across festivals and other occasions.

The CTI's position comes amid continuing concerns over Delhi's air quality and the contribution of different sources to pollution during the winter months. While the IITM estimates identified firecrackers as the largest contributor in the immediate post-Diwali period, Goyal argued that a broader approach was needed to tackle the city's pollution.