Air Pollution In India: Understanding The Major Causes

Air pollution is a pressing issue in India, causing approximately 2 million deaths annually and leading to health issues such as respiratory and cardiovascular diseases. India's rapid population and technological growth, coupled with geographical constraints, have made it one of the most polluted countries globally. Industrial emissions, vehicular emissions, construction dust, waste burning, and the use of biomass for cooking and heating are significant contributors to India's poor air quality. These factors, along with climate change impacts, have resulted in India having the highest number of highly polluted cities, with Delhi being one of the top three polluted cities in the world.

Industrial and vehicular emissions

India is one of the most polluted countries in the world, with 2 million deaths attributed to air pollution every year. The country has launched the National Clean Air Program to reduce particulate matter pollution by 30% by 2024.

Industrial pollution is the main contributor to India's air pollution, accounting for 51% of the total. This includes emissions from factories, power plants, and other combustion sources that burn fossil fuels such as fuel oil, gasoline, and natural gas. These combustion sources emit harmful gases such as sulfur dioxide, nitrogen dioxide, and carbon monoxide directly into the air.

Vehicular emissions, on the other hand, contribute to 27% of India's air pollution. The high number of vehicles on the roads, coupled with traffic congestion, leads to a significant increase in tailpipe emissions. Taxis and auto-rickshaws often run on adulterated fuel blends, which further worsen air quality. This adulteration of fuel involves mixing gasoline and diesel with lower-priced fuels like kerosene, which increases emissions of harmful pollutants. The result is a higher release of tailpipe emissions, including hydrocarbons, carbon monoxide, oxides of nitrogen, and particulate matter.

The problem of vehicular emissions is particularly acute in cities like Delhi, which has a population of 25 million and a high density of vehicles on its roads. The city's geographic location, surrounded by mountains, also plays a role in trapping pollutants during the colder months. The combination of industrial and vehicular emissions, along with other sources of pollution, makes Delhi one of the most polluted cities in India and the world.

To address these issues, India has implemented programs like the Pradhan Mantri Ujjwala Yojna, which aims to improve access to clean energy options like LPG for marginalized households. Additionally, there is a growing recognition of the need for a shift in transportation strategies and the adoption of cleaner fuels to reduce vehicular emissions.

Construction dust and debris

The Indian government has implemented several measures to reduce air pollution from the construction sector. The Commission for Air Quality Management (CAQM) has put into action the Graded Response Action Plan (GRAP) in Delhi NCR to regulate air pollution levels. This plan targets high-polluting sectors, such as construction, and imposes restrictions on their activities during periods of high pollution. For example, during the earlier stages of poor air quality, the government may require the use of anti-smog guns, water sprinklers, and dust suppression measures at construction sites. In the most severe stage, the government may impose a complete ban on all construction activities to improve air quality.

To assess the effectiveness of these measures, the Council on Energy, Environment and Water (CEEW) has initiated a pilot study at a construction site in Gurugram. This study involves monitoring the intensity of dust emissions from different construction activities and evaluating the impact of mitigation strategies. Certain activities, such as excavation, demolition, and vehicle movement on unpaved roads, generate high levels of dust emissions and significantly contribute to air pollution. By implementing effective dust control measures for these activities, there can be a substantial reduction in PM concentration levels.

Despite these efforts, air pollution in India remains a critical issue. In 2019, India was ranked seventh among the countries most affected by climate change. The country emits about 3 gigatonnes of CO2eq of greenhouse gases annually, with per capita emissions lower than the world average. However, India's emissions contribute to 7% of global emissions, despite the country having only 17% of the world's population.

Thermal power dependence

India's dependence on thermal power for electricity is a significant contributor to its air pollution problem. In 2024, thermal power plants in the country were found to emit many times more PM2.5 and sulphur dioxide than stubble burning, with plants in the national capital region of Delhi releasing 16 times more air pollutants than straw burning in Punjab and Haryana. According to the Centre for Research on Energy and Clean Air, thermal power plants in Delhi release 281 kilotonnes of SO₂ annually, while burning 8.9 million tonnes of paddy straw emits just 17.8 kilotonnes.

The Indian government has been criticised for its lenient enforcement of emission controls on thermal power plants, with these facilities benefiting from repeated deadline extensions for installing flue gas desulfurization (FGD) systems. The Ministry of Power has requested a 36-month extension to the deadline, citing "major constraints" in domestic manufacturing capacity, import dependence, and sudden growth in demand. However, installing FGD in thermal power plants can significantly reduce emissions of sulphur dioxide, with studies showing a potential reduction of up to 64%.

The impact of thermal power plants on air pollution is particularly severe in Delhi, where the Air Quality Index (AQI) has reached severe levels, posing health risks to both healthy individuals and those with pre-existing conditions. The city's 24-hour AQI stood at 441 on November 17, 2024, making it the second-most polluted city in India. While seasonal crop-residue burning contributes to spikes in air pollution, thermal power plants are a constant source of combustion, releasing harmful pollutants into the atmosphere year-round.

To address the issue of thermal power plant emissions, India has implemented the National Clean Air Program, which aims to reduce particulate matter pollution by 20-30% by 2024. The program includes initiatives such as upgrading fossil fuel combustion engine vehicles to BS6 emission standards and encouraging the use of electric vehicles, with a goal of 25% of private vehicles being electricity-powered by 2023. Additionally, India has committed to reducing the number of households using solid fuel for cooking and has introduced electric public transport buses to its fleet.

Waste burning

The burning of waste, particularly municipal solid waste, releases harmful particulate matter (PM2.5 and PM10), carbon monoxide, and other non-methane volatile organic compounds (NMVOCs). These toxic fumes pose severe health risks, including respiratory problems, cardiovascular complications, and cognitive impairment. They particularly affect vulnerable groups such as the elderly and children.

In addition to municipal waste, the burning of garden waste is also a common occurrence in many Indian cities. This practice further contributes to the deterioration of air quality. To address this issue, it is crucial for municipal corporations and city governments to acknowledge the problem and implement proactive measures. Decentralized waste management systems at the community and ward levels can help reduce the burden on centralized locations, lower transport costs, and decrease the likelihood of dumping and burning waste.

Paddy-residue burning, a common practice in northwest India during October and November, is associated with poor air quality in the region. It contributes to the formation of secondary pollutants such as secondary organic aerosol (SOA) and ozone. Additionally, the burning of biomass, fuelwood, and agricultural waste is a primary reason for the near-permanent haze and smoke observed above rural and urban India. India is the world's largest consumer of fuelwood, agricultural waste, and biomass for energy purposes, with over 100 million households relying on these fuel sources for cooking and heating.

To combat waste burning and improve air quality, India has implemented initiatives such as the National Clean Air Programme, which aims to reduce particulate matter pollution by 20%-30% by 2024.

Use of wood and dung for cooking

India has over 1.3 billion people, and over two-thirds of them rely on carbon-emitting biomass, wood, and dung-based fuel for cooking. Dung-based fuel is especially popular because it is easily available for free in rural areas. However, the use of wood and dung for cooking is a major source of indoor air pollution, which causes millions of premature deaths every year.

According to a World Health Organization report, over 50% of premature deaths among children under five are due to pneumonia caused by particulate matter (soot) inhaled from household air pollution. The report adds that there are also over 3.8 million premature deaths annually from non-communicable diseases such as stroke, ischemic heart disease, chronic obstructive pulmonary disease, and lung cancer that are attributed to exposure to household air pollution.

The use of wood and dung for cooking in India releases disproportionately large quantities of air pollution. Dried cow dung, a primary source of household cooking fuel for many in rural India, releases more particulate matter across the country than wood and other biofuels. Dung stoves emitted an estimated 1,600 gigagrams of PM2.5 in 2020, about half of all residential sector PM2.5 emissions and 17% more than wood stoves (~1,370 gigagrams). However, less than 10% of Indian households used dung stoves that year, whereas more than 40% used wood stoves.

The prolific use of this cheap fuel in the absence of clean sources of energy causes staggering damage to human health, especially to the women and children of the house. Women in rural areas end up investing valuable time and effort into collecting fuel instead of focusing on their children's education or income generation possibilities. Furthermore, the carbon-containing gases released from biomass fuels are many times more reactive than cleaner fuels such as liquefied petroleum gas.

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