Delhi's Air Pollution: Worsening Yearly Crisis

Delhi, the capital territory of India, has been dubbed the most polluted city in the world. The air pollution in Delhi is a public health emergency that has been linked to about 2 million deaths in India every year. The air quality in Delhi has been worsening every year, with the Air Quality Index (AQI) rising above 400, a level deemed ''hazardous'' by the World Health Organization. The primary sources of pollution in Delhi include vehicle emissions, industrial pollution, crop burning, construction activities, landfills, and agricultural practices. The increase in air pollution in Delhi can be attributed to a combination of natural and human-made pollutants, with the city's rapid urbanization, growing traffic congestion, and lack of stringent environmental regulations exacerbating the problem.

Transport and vehicles

Delhi, the capital territory of India, has been dubbed the most polluted city in the world. The air pollution in Delhi affects the surrounding districts, and it is estimated that it kills about 2 million people every year. According to a 2018 research paper by India's Ministry of Earth Sciences, vehicular emissions contribute to almost 41% of air pollution. The transport sector's impact on air pollution increases during the winter season, contributing to approximately 23% of PM2.5 levels.

The local on-road transport sector contributes the largest amount to diurnal mean PM2.5 during the evening traffic peak. Two- and three-wheelers contribute 50% of this, followed by heavy-duty vehicles at 30%. Cars, buses, and trucks emit carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). Vehicles contribute 20% of PM2.5 and 36% of NOx emissions.

In an attempt to reduce vehicular air pollution, the Delhi government has implemented several measures. In 2021, the government banned the entry of commercial petrol and diesel vehicles into Delhi. Additionally, starting in April 2025, fuel stations will stop providing fuel to vehicles older than 15 years. The Delhi government also plans to add 1,000 extra CNG buses to the fleet, and the Civil Defense Unit will randomly check the registrations and pollution certificates of cars.

To address the pollution problem, campaigners urge leaders to tackle transport and heavy industry rather than seek quick fixes. An initiative being considered is the creation of a 1,600-kilometer-long and 5-kilometer-wide green ecological corridor along the Aravalli Range from Gujarat to Delhi, connecting to the Sivalik Hills range. This initiative would involve planting 1.35 billion new native trees over 10 years to combat pollution.

Industrial emissions

Delhi's air pollution is a public health emergency, with the city regularly ranked as the world's most polluted. Industrial emissions are a significant contributor to this crisis.

Factories and power plants release large amounts of harmful gases, including sulphur dioxide (SO2) and nitrogen oxides (NOx). About 90% of Delhi's SO2 emissions come from industrial sources. These emissions, along with other pollutants, contribute to the formation of secondary pollutants like ozone, which further exacerbates the problem.

The burning of crop stubble in neighbouring states, such as Punjab, Haryana, and Uttar Pradesh, is another major source of industrial pollution. Farmers in these states burn crop residues to clear fields after the harvest, releasing massive amounts of smoke and harmful particles into the air. This practice has been partially mitigated in recent years, with incidents of stubble burning in Punjab dropping by 42.8% between 2021 and 2024. However, Haryana saw a sharp rise in stubble burning in 2023, with a 222.6% increase in incidents over the previous year.

The Delhi government has implemented various measures to combat industrial pollution, including shutting down highly polluting power plants, such as the Badarpur power plant, and forming the Commission for Air Quality Management to enforce pollution control measures. Additionally, the government has urged Punjab to revisit the 2009 water law, which contributes to late paddy sowing and encourages stubble burning.

Despite these efforts, industrial emissions continue to play a significant role in Delhi's air pollution crisis, with the city's air quality index (AQI) regularly reaching hazardous levels. As such, there is a critical need for further action to address this issue and improve the health and well-being of Delhi's residents.

Crop burning

Delhi has consistently been ranked as one of the most polluted cities in the world. The poor air quality in the city has been attributed to several factors, one of which is crop burning.

However, crop burning has severe negative impacts on the environment and human health. The fires release harmful pollutants into the air, including particulate matter (PM2.5), carbon monoxide, nitrogen oxides, and other toxic substances. These pollutants can remain in the atmosphere for extended periods, affecting air quality not just in local areas but also in nearby cities like Delhi. The dispersion of these pollutants can lead to smog formation and hazardous levels of air pollution, posing significant health risks, especially during the winter months when wind speeds are low.

In Delhi, crop burning has been identified as a significant contributor to the city's air pollution crisis. While it may not be the dominant factor, it plays a crucial role in the severe air quality issues the city faces annually. Studies have shown that crop burning can account for up to 50% of Delhi's pollution during the early winter period, with more recent estimates placing it at around 30%. The impact of crop burning is particularly evident in the significant spike in the Air Quality Index (AQI) levels during this time.

To address the issue of crop burning and its impact on air pollution in Delhi, various measures have been proposed and implemented. These include:

• The Commission for Air Quality Management was formed to enforce pollution control measures in the National Capital Region, including Delhi.
• The Punjab government launched the MSP scheme for alternative crops to encourage farmers to reduce stubble burning.
• The Supreme Court advised the Punjab government to reconsider the 2009 water law, which contributes to late paddy sowing and promotes stubble burning.
• The implementation of the Graded Response Action Plan (GRAP), which categorizes air quality into four stages and triggers stricter pollution control measures as the air quality deteriorates.

Construction and road dust

Delhi, the capital territory of India, has been dubbed the most polluted city in the world. The air pollution in Delhi is estimated to kill about 2 million people every year, with 2.2 million children suffering irreversible lung damage. The city's poor air quality has been attributed to various factors, one of which is construction and road dust.

Construction sites, the production of raw materials such as bricks and concrete, and the dust kicked up by cars on Delhi's extensive and expanding road network all contribute significantly to the city's air pollution. A 2015 study of 19 large Delhi construction sites revealed that the air quality around them exceeded safe limits by a significant margin, with workers being exposed to high levels of dust and pollutants. The city's construction industry has been described as unregulated, and the dust produced by these sites and the roads has severe health implications, particularly for children and the elderly.

Road dust, in particular, has been identified as a major contributor to Delhi's air pollution. According to a 2016 study by IIT-Kanpur, road dust accounts for 56% of the overall pollution in the national capital. The dust particles released by traffic are highly toxic as they mix with vehicular emissions and industrial pollution. These harmful pollutants settle in the air and can have severe respiratory health effects.

The Delhi government has recognized the urgency of the situation and launched anti-dust campaigns to curb air pollution. These campaigns aim to enforce dust control guidelines at construction sites and ensure that contractors follow the mandated measures. The government has also created a 'dust pollution control self-assessment portal' to strengthen its anti-dust initiatives. However, despite these efforts, the problem persists, and the city continues to grapple with the harmful impacts of construction and road dust on its air quality.

In addition to the immediate health risks, the construction and road dust also have long-term economic implications. The poor air quality discourages businesses and talent from settling in the city, hindering its economic growth and development. The high levels of pollution also strain the healthcare system, as more people require treatment for respiratory and other health issues caused by the polluted air.

Fireworks and firecrackers

The burning of firecrackers during Diwali releases harmful pollutants into the air, including particulate matter (PM 2.5 and PM 10), metals, and SO2. These emissions have severe health impacts on Delhi's residents, particularly those with existing respiratory conditions. Hospitals in Delhi have reported a sharp rise in respiratory cases during this period, and vulnerable individuals are advised to stay indoors or use protective masks when going outside.

The Supreme Court of India has recognized the issue and, in 2017, banned the sale of fireworks in Delhi ahead of Diwali. Despite this ban, many residents continue to use traditional firecrackers during the festival, and the city's air quality deteriorates further in the aftermath of Diwali.

The impact of fireworks and firecrackers on Delhi's air pollution is exacerbated by other factors, such as stubble burning in nearby states and emissions from vehicles, industries, and construction activities. The combination of these sources leads to sustained air pollution events, affecting public health and quality of life across the region.

Addressing the issue of fireworks and firecrackers during Diwali is crucial in mitigating Delhi's air pollution crisis. Regulatory interventions and public awareness campaigns are necessary to reduce the use of traditional firecrackers and encourage the adoption of alternative celebration methods that do not compromise the city's air quality.

Frequently asked questions