Delhi’s annual Diwali air pollution problem triggers renewed calls for stronger measures to protect public health

According to India’s Central Pollution Control Board (CPCB), PM2.5 levels in several areas of the Delhi-National Capital Region (NCR) reached 900 micrograms per cubic metre – over 15 times the ‘safe’ level of 60 micrograms per cubic metre on the evening of Thursday 31 October, at the start of the annual Hindu festival. PM2.5 is fine particulate matter with a diameter of less than 2.5 micrometres, that can infiltrate the lungs and occasionally enter the bloodstream, and has been linked to cancer, diabetes and other life-shortening conditions.

At 6am on Friday 1 November, the Air Quality Index (AQI) was recorded at 359, which falls in the ‘very poor’ category set by the CPCB, reported India Today newspaper. An AQI between zero and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, 401 and 450 ‘severe’ and above 450 ‘severe plus’.

In Delhi's neighbouring areas, such as Faridabad, Greater Noida, Ghaziabad, Gurugram and Noida, the air quality was slightly better, although all of them still were in the ‘poor’ category on Thursday, reported India Today.

Ban on firecrackers flouted

The poor air quality arose despite the Delhi government imposing a ban on the production, storage, sale and use of firecrackers, from 14 October until 1 January 2025. On Wednesday 30 October, just before Diwali, Delhi’s Environment Minister Gopal Rai announced that 377 teams had been formed to enforce the ban on firecrackers across Delhi-NCR. He said authorities were in touch with resident welfare associations, market associations and social organisations to spread awareness, in a bid to prevent fireworks contributing to the city and region’s general poor air quality.

An official told India Today that legal action would be taken against those found to be setting off firecrackers.

However, despite the ban and promises of strong enforcement, fireworks were reported in multiple neighbourhoods in Delhi-NCR, reported India Today.

Penalties doubled for stubble burning

Meanwhile, in a separate move, around a week after Diwali, on 7 November, the Ministry of Environment, Forest and Climate Change doubled the penalties for agricultural stubble burning in the region around Delhi-NCR, after the capital’s overall AQI remained in the ‘very poor’ category, according to the CNBCTV news website. Stubble burning is a cheap and effective method of clearing fields for the next sowing cycle, employed by farmers in western Uttar Pradesh (UP), Punjab and Haryana, but contributes to Delhi’s air pollution.

Earlier, on 14 October, the Commission for Air Quality Management (CAQM) announced it was sending 26 teams of inspectors into the states of UP, Punjab and Haryana in a bid to prevent stubble burning. The move came after India’s Supreme Court criticised the CAQM for failing to bring any prosecutions against farmers for stubble burning, and criticised the Punjab and Haryana governments for failing to take suitable steps tp prevent stubble burning, reported CNBCTV.

Residents report breathing problems

Every autumn, the air quality in Delhi-NCR deteriorates and residents complain of sore throats, itchy and watery eyes and eye strain, among other problems. Several hospitals in the city also see a rise in the number of patients with respiratory problems.

A survey report revealed that at least 69 per cent of families in the capital and surrounding region have one or more members suffering from pollution-related illness including sore throats, breathing issues and cough.

A digital platform, Local Circles, surveyed more than 21,000 residents across the Delhi-NCR area about the harmful impact of air pollution on them. The survey found that 89 per cent of Delhi-NCR families either had or have someone suffering from sore throat and cough and 78 per cent have someone who has suffered or is suffering from breathing difficulties.

The survey also revealed that 62 per cent of families have one or more members experiencing burning eyes due to rising air pollution, while 46 per cent have someone with a runny nose or congestion.

As well as a failure to stamp out stubble burning, instances of rubbish burning and the continued practice of manual road sweeping despite the poor air quality in Delhi-NCR have left many people wondering if the city and central government and regulators are taking sufficient action to address the root causes of air pollution.

Although the central and Delhi governments have repeatedly promised action and announced measures aimed at preventing the catastrophic levels of autumn and winter pollution that have become an annual event in Delhi-NCR over the past decade, the air pollution crisis continues.

So, why does air quality in Delhi-NCR deteriorate during October and November?

Constant pollution

Experts says Delhi's QI deteriorates due to constant pollution from vehicular emissions, dust, industrial sources, and episodic human activities, including the setting off of firecrackers and stubble burning.

Although stubble burning is illegal in India, the ban is poorly enforced. Farmers in northern India, including Punjab, Haryana, and other regions, are attracted to stubble burning because it an easy and cost-effective way to clear the stubble left on the field after the paddy harvest, and prepare for the next planting season. The practice is a cheaper and quicker alternative to manually or mechanically removing crop residue.

However, the smoke released due to husk burning pollutes the air and produces a haze of pollutants that induces a ‘toxic atmosphere’ in Delhi.

In a study, Stubble Burning in India: Environmental Concern and Alternative Tools, by the Department of Chemistry, Government College, Hisar, Haryana, the authors say it is possible to transform stubble into something valuable in a number of ways, such as the production of electricity from biomass, domestic animal feed, or even the production of necessary end products, such as medicines, health products and composts. Furthermore, addition of crop left-overs into the soil can also improve the physical, chemical and biological qualities of soil in a number of ways, they say.

However, despite the CAQM receiving 454 reports of illegal stubble burning in Punjab and Haryana alone in the period 15 September – 9 October 2024, progress has been made in reducing the harmful practice. NASA’s Visible Infrared Imaging Radiometer Suite (VIIRS) data indicated a 51 per cent drop in the total number of farm fires between 2018 and mid-October 2024. 

Meanwhile, a report by air quality solutions company Airvoice revealed that although the use of fireworks during Diwali raises pollution levels significantly, the effects only persist for around 24 hours, after which air quality improves.

“Diwali night is particularly challenging for cities already struggling with pollution,” said Col. Ashwini K. Channan, CEO of Airvoice India. “Our study shows that even with regulation, Diwali’s environmental impact remains significant, underlining the need for better compliance and innovative solutions that honour cultural traditions while protecting public health.”

The Delhi government banned the use of firecrackers for Diwali back in 2017, however, the PM2.5 concentration on the night of Diwali in 2024 in the city and region was 100 per cent higher than on any regular day in 2023.

Water sprayed on roads

Meanwhile, in a separate move aimed at improving air pollution, Delhi environment minister Gopal Rai announced the deployment of 200 mobile ‘anti-smog guns’ across all 70 assembly constituencies, actively spraying water on roads to minimise dust and further mitigate pollution levels.

“The government is implementing various initiatives to combat pollution, including an anti-dust campaign, bio-decomposer spraying, a tree plantation drive, and a public awareness campaign on the impact of firecrackers,” he noted.

However, experts say no research has shown that sprinkling water is an effective way of reducing air pollution and, if there are benefits, they are likely to be only temporary.

Environmental campaigner Bhavreen Kandhari told Press Trust of India: “If you sprinkle some water, it'll have an effect for just a couple of hours, but in the long run, systematic changes are needed.”