Diwali's Dark Side: Festival Of Lights' Pollution Problem

The Diwali festival, celebrated in India, is also known as the festival of lights. Fireworks have been a part of the celebrations since around 1400 AD. However, in recent years, there has been growing concern about the impact of Diwali on air pollution levels, particularly in Delhi, which is one of the most polluted cities in the world. Studies have shown that the burning of firecrackers during Diwali leads to a significant increase in air pollution, with PM2.5 levels surging to dangerous levels. In addition to firecrackers, other factors contributing to pollution during Diwali include the burning of farm stubble in neighbouring states and increased vehicle traffic. While some Indian states have banned or restricted the use of firecrackers during Diwali, the enforcement of these bans has been weak, and the issue of Diwali-related pollution persists.

Firecrackers cause an 875% spike in pollution

Diwali is a religious festival celebrated in India, and like many festivals, it is an occasion for fireworks and firecrackers. However, the burning of firecrackers during Diwali has been linked to a significant increase in air pollution across the country, particularly in northern states such as Delhi, Uttar Pradesh, and Haryana, which are already struggling with poor air quality.

A recent report by Airvoice, an air quality control startup, revealed that pollution caused by Diwali firecrackers surged by a staggering 875% in some regions of India. The study, which analysed data from 180 air quality monitoring stations across 14 states between 2017 and 2023, highlighted a dramatic rise in PM2.5 levels—dangerous fine particulate matter known to cause severe health risks.

On Diwali night, PM2.5 levels in several northern states exceeded the National Ambient Air Quality Standards (NAAQS) limits by up to 875%. This is particularly concerning as PM2.5 particles are small enough to be inhaled, causing severe health risks. The report also found that despite the ban on firecrackers in some cities, PM2.5 levels on Diwali night in 2023 were still 100% higher compared to years when firecrackers were allowed, indicating the limited impact of firecracker bans.

The study further warns of the long-term presence of harmful metals like aluminium, manganese, and cadmium released by firecrackers. These toxic substances can remain in the air even after the initial pollution spike, posing significant respiratory risks long after the festival smoke clears. This finding underscores the need for stricter enforcement of firecracker bans and the exploration of more innovative solutions to reduce pollution spikes during cultural celebrations.

While the air quality tends to normalise within 24 hours, the drastic increase in pollution during Diwali celebrations cannot be overlooked. The report highlights the need for more monitoring stations and innovative pollution control solutions that respect cultural traditions. It is essential to strike a balance between cultural celebrations and environmental sustainability to ensure the well-being of both the people and the planet.

Firecrackers release toxic metals

The burning of firecrackers during Diwali releases toxic metals into the atmosphere, causing a significant increase in air pollution and posing serious health risks. A recent report by Airvoice, an air quality control startup, revealed an 875% spike in pollution levels in some regions of India on Diwali night. This drastic rise in pollution is attributed to the toxic metals and chemicals released by firecrackers.

The presence of hazardous metals and metal oxides in firecrackers has been confirmed by chemical analyses conducted by environment groups and laboratories. These toxic substances, including lead, chromium, copper, phosphorus, sulphur, chlorine, aluminium, and metal oxides such as sulphur trioxide, phosphorus pentoxide, and vanadium pentoxide, are listed as hazardous and toxic chemicals under the Manufacture, Storage, and Import of Hazardous Chemicals Rules 1989. Despite a ban on the sale and use of fireworks during Diwali celebrations in several Indian states, the enforcement of this ban has been weak, and firecrackers continue to be widely used.

The health implications of burning firecrackers are severe. The toxic metals released can cause respiratory problems and pose risks to almost every organ in the body. Lead, for example, emits highly toxic fumes when heated, affecting the brain and nerves. Long-term exposure to lead can result in developmental delays and learning disabilities, especially in children. Manganese dust and fumes can cause lung irritation, muscle rigidity, tremors, and even paralysis. Zinc, while not inherently toxic, can emit toxic fumes when burned, causing metal fume fever.

The release of toxic metals from firecrackers during Diwali has significant and far-reaching consequences for public health and the environment. The Indian government's Central Pollution Control Board has listed 15 hazardous and toxic substances found in fireworks, urging people to opt for a "'green Diwali' and refrain from burning firecrackers. Despite the ban, the surge in pollution levels on Diwali night underscores the need for stricter enforcement and the development of more effective strategies to curb pollution without compromising cultural traditions.

Farm fires contribute to pollution

Farm fires are a significant contributor to the pollution caused by Diwali celebrations. Farmers in northern India burn off crop stubble to prepare the ground for the next round of crops. This practice, known as stubble burning, is a major source of air pollution in the region, leading to disruptions such as school closures and construction curbs. While there has been a ban on stubble burning since 2015, it is still widely practised, especially in states like Punjab, Haryana, and Uttar Pradesh, which have a high share of farm fire incidents.

The smoke from these fires, along with emissions from firecrackers during Diwali, contributes to the deterioration of air quality in Delhi and surrounding areas. In 2021, a week after Diwali, farm fires contributed to 48% of PM2.5 levels, which are harmful particles that can be inhaled. While the contribution of farm fires to pollution can vary depending on wind speed and direction, it is a significant factor in the overall air quality of the region.

The impact of farm fires on air quality is complex and dynamic. For example, in 2024, there was a unique trend where PM2.5 pollution spiked sharply at night during Diwali and dissipated more quickly the next day compared to previous years. This trend may be influenced by factors such as wind direction and atmospheric conditions. Additionally, the contribution of farm fires to pollution can be influenced by the timing of Diwali. When the festival is celebrated earlier in the year, as in October, the impact of farm fires may be reduced as the weather is typically warmer, leading to more efficient natural ventilation.

While efforts to reduce stubble burning have been made, such as a decrease in farm fire incidents in 2024, the practice continues to be a significant contributor to pollution during Diwali. The complex interplay between farm fires, firecracker emissions, and local pollution sources, such as vehicle emissions, highlights the need for comprehensive strategies to address the issue effectively.

Overall, farm fires play a significant role in the pollution caused by Diwali, and addressing this issue requires a multi-faceted approach that considers local pollution sources and finds alternatives to stubble burning.

Vehicle emissions increase during Diwali

Diwali, a religious festival celebrated in India, has been associated with increased pollution levels, particularly in the capital city of Delhi, which is already one of the most polluted cities worldwide, especially during the winter months from October to January. While fireworks and the burning of farm stubble have been identified as significant contributors to air pollution during Diwali, vehicle emissions also play a notable role.

During the Diwali period, vehicle traffic increases as people travel to visit family and friends and buy gifts. This rise in traffic leads to higher vehicle emissions, which contribute to the overall pollution levels. In Delhi, vehicles were identified as the largest local source of pollution during Diwali week in 2022, according to an assessment by the Centre for Science and Environment (CSE). The study found that vehicles accounted for nearly 17% of the total PM2.5 concentration when considering all pollution sources, including those from beyond Delhi. However, if only local sources in Delhi are considered, the transport sector contributed almost half (49.3%-53%) of the PM2.5 concentration during that week.

The increase in vehicle emissions during Diwali can be attributed to several factors. Firstly, the higher number of vehicles on the road results in longer congestion, which lowers the average speed of traffic. This reduced speed leads to higher emissions, including nitrogen dioxide, as vehicles spend more time on the road. Additionally, the impact of vehicle emissions is compounded by other sources of pollution during Diwali, such as fireworks and farm fires, which also contribute significantly to the degradation of air quality.

It is important to note that the issue of vehicle emissions during Diwali is not an isolated incident. Delhi, in particular, has been struggling with poor air quality, and the festival's activities further exacerbate the problem. The Indian government has implemented measures such as restricting cars on certain days (the odd-even rule) to improve air quality, but the effectiveness of these interventions is still under evaluation.

To address the issue of increased vehicle emissions during Diwali, several strategies can be considered. These include improving public transportation systems, promoting electrification of vehicle fleets, developing walking and cycling infrastructure, implementing low-emission zones, and introducing vehicle restraint measures such as parking caps and pricing adjustments. By combining these approaches, it may be possible to reduce the environmental impact of vehicle emissions during the Diwali festival and improve air quality for the residents of Delhi and other affected areas.

Soil and water pollution from firework debris

Fireworks are a major source of pollution, particularly air pollution, as evidenced by the spike in PM2.5 levels on Diwali night. However, their impact on soil and water quality is also significant and often overlooked.

Perchlorate, a chemical compound often added to fireworks to facilitate their upward propulsion, is a common contaminant of soil and water. This chemical has been detected in both soil and water samples at fireworks display sites, such as Mount Rushmore National Memorial in the US and Kerala, India. Perchlorate has been found to affect the function of the thyroid gland in large amounts and can also impact fish development when it ends up in water bodies.

In addition to perchlorate, fireworks can release other chemicals and metals that pollute the soil and water. These include aluminium, manganese, and cadmium, which pose respiratory risks if inhaled and can have long-term effects on human health. The particulate matter from fireworks can alter the nutrients in the soil, leading to more acidic surface water, which can severely impact ecosystems.

Firework debris, such as shells and heavy metals, can be scattered across the ground, providing opportunities for animals to accidentally ingest hazardous materials. This can lead to illnesses and even death in wildlife. Additionally, fireworks contribute to microplastic pollution in water, with plastic particles 5mm in diameter and less being released during firework displays. The River Thames in England experienced a shocking increase in microplastic content following the New Year's Eve firework show.

To minimise the impact of fireworks on soil and water quality, several measures can be taken. These include the use of low-perchlorate fireworks, proper disposal of firework debris, and the implementation of policies prohibiting fireworks in certain areas, as seen in Zhengzhou, China, in 2016. Homeowners and businesses can also opt for alternative celebrations, such as parades or local block parties, to help reduce pollution and protect the environment.

Frequently asked questions