India's Air Pollution: A Man-Made Disaster

India is one of the most polluted countries in the world, with air pollution causing one in eight deaths. In 2019, 21 of the world's 30 most polluted cities were in India, and the country's capital, New Delhi, has the poorest air quality among capital cities globally. India's air pollution is a multifaceted issue, with vehicular pollution, industrial emissions, thermal power plants, construction dust, waste burning, and the burning of biomass for cooking and heating being the main contributors. The country's fast-growing economy, geographical barriers, and environmental factors also play a role in exacerbating the problem. While India has taken initiatives to combat air pollution, such as the National Clean Air Program, the progress has been inconsistent, and air pollution remains a pressing public health concern.

Vehicular emissions

India is the world's fourth most significant emitter of greenhouse gases, contributing to 7.08% of global emissions. The country has one of the highest compound annual growth rates (10%) of vehicle registrations, and the transport sector accounts for a quarter of total emissions. Vehicular emissions are a major cause of air pollution in urban areas, contributing 20-30% of particulate matter (PM) 2.5 at the breathing level of air quality. PM2.5 refers to particles with a diameter of less than 2.5 micrometres, which is about one-thirtieth the width of a human hair and can cause deadly illnesses such as lung cancer, stroke, and heart disease.

Vehicles emit pollutants such as nitrogen oxides (NOx), which contribute to the formation of ground-level ozone, a deadly secondary gas linked to respiratory diseases and asthma. Indian cities like New Delhi, Bangalore, Mumbai, and Kolkata have some of the highest levels of NOx in the country, which is linked to vehicular pollution. The transport sector contributes to a third of India's PM pollution and 27% of overall air pollution in the country.

To address vehicular emissions, India has adopted the Modified Indian Drive Cycle (MIDC), which accounts for wider speed profiles and is better suited for representing real-world driving conditions. However, the MIDC may still not adequately represent on-road emissions due to variations in traffic density, land-use patterns, road infrastructure, and poor traffic management. As a result, there has been a shift towards adopting the Worldwide Harmonized Light Vehicle Test Procedures (WLTP), a global standard for determining pollutant levels from internal combustion engine (ICE) and hybrid cars.

In terms of emission standards, the Indian government has mandated the manufacture, sale, and registration of BS-VI (BS6) vehicles from April 2020. Additionally, there is a proposed roadmap for the gradual rollout of ethanol-blended fuel, with a target of achieving E10 fuel supply by April 2022 and a phased rollout of E20 from April 2023 to April 2025. These initiatives aim to reduce vehicular emissions and improve air quality in India.

Furthermore, India is preparing to introduce significant reforms in 2023 to improve vehicle testing procedures and control real-world emissions. The International Centre for Automotive Technology in India is developing Real Driving Emissions (RDE) procedures, which will account for various conditions such as altitudes, temperatures, vehicle payloads, and road types. These procedures are expected to come into force in 2023, further enhancing the accuracy of emissions testing and helping to keep vehicles low-emitting on roads.

Industrial emissions

India's air pollution levels are among the highest in the world, severely impacting the country's health and economy. Industrial emissions are a major contributor to this issue, with 51% of India's air pollution stemming from industrial sources.

Industrialization has brought economic development to India, but it has also had detrimental effects on human health and the environment. Rapid growth in industrial production has led to poor air quality in many Indian cities and industrial clusters. Out of the 30 most polluted cities globally, 21 were in India in 2019, with New Delhi frequently ranking in the top five.

Various industries in India have the potential to negatively impact air quality, including chemical, textiles, cement, steel, basic metal, mining, petroleum refineries, and thermal power plants. These industries emit pollutants through the use of fossil fuels, industrial boilers, furnaces, vehicles, and other activities. The lack of standardized tools and consistent data formats across India makes it challenging to accurately track and address industrial emissions.

The Indian government has taken some initiatives to address air pollution, such as launching the National Clean Air Programme in 2019, aiming for a 20-30% reduction in PM2.5 and PM10 concentrations by 2024. Additionally, the Aerosol and Air Quality Research Facility was established in collaboration with Washington University in St. Louis to study air pollution in the country.

To effectively tackle industrial emissions, India needs to adopt a multi-sectoral and multi-jurisdictional approach, as air pollution affects regions beyond its major cities. Standardizing tools and data across the country is crucial for implementing successful control strategies and linking relevant data sets. By improving transparency and accountability in industrial emissions data, India can better address the air pollution challenge and work towards reducing emissions.

Crop burning

India's air pollution levels are among the highest in the world, and crop burning is a significant contributor to this issue. In autumn and spring, large-scale crop residue burning in agricultural fields is a cheaper alternative to mechanical tilling, releasing smoke, smog, and particulate pollution. This practice is particularly prevalent in the northwestern states of Punjab and Haryana, where wheat and rice are the principal crops grown under a crop rotation system. The tight schedule of the harvest-to-sowing transition in this system makes it challenging to adopt alternatives to burning.

Crop residue burning allows for the cheap and fast disposal of crop residue, and satellite data from NASA has revealed a ~60% increase in agricultural fires between 2002 and 2016. This increase in burning has severe consequences for air quality, with a concurrent ~60% increase in aerosol loading over the Indo-Gangetic Plain and a ~45% increase during the post-monsoon agricultural burning months. The particulate matter (PM2.5) and trace gases released from crop burning can severely affect local and regional air quality, triggering changes in atmospheric chemistry and potentially altering the Earth's radiation balance.

The adverse health impacts of crop burning are significant. Air pollution is the top preventable cause of mortality in many low- and middle-income countries, including India, and epidemiological studies have shown that any additional exposure to PM2.5 increases the risk of premature mortality, even at low baseline exposure levels. The National Capital Region (NCR) of Delhi, in particular, is severely affected by crop waste burning in neighbouring states, with northwesterly wind flows distributing carbonaceous smoke particles over a wide area. Poor air quality in northern India is estimated to reduce life expectancy by six to nine years for half a billion people, and the economic costs of air pollution-related premature deaths and morbidity are substantial.

To address the issue of crop burning, the Indian government has introduced various measures, including a ban on burning residue with punishable fines since 2015. However, enforcing these penalties across jurisdictions has been challenging due to the spread of smoke and a powerful farmer lobby. As an alternative approach, Payment for Ecosystem Services (PES) contracts have been proposed, where cash transfers are conditional on not burning crop residue. A randomized controlled trial in Punjab found that PES contracts with partial upfront payments reduced crop residue burning by 10 percentage points, potentially due to increased trust and eased liquidity constraints for farmers.

Overall, crop burning is a significant contributor to India's severe air pollution problem, particularly in the northwestern states. The practice has detrimental effects on air quality and public health, and addressing it requires a combination of punitive measures and incentive-based approaches such as PES contracts.

Thermal power plants

India's thermal power plants emit harmful pollutants into the atmosphere, contributing significantly to the country's poor air quality. These emissions include sulphates, nitrates, mercury, and heavy metals, which have severe ecological and public health impacts. Coal-fired power plants are a major source of toxic pollutants, and in India, coal-based power plants generate about 75% of the country's electricity.

The main pollutants emitted by thermal power plants are sulphur dioxide (SO2) and fine particulate matter (PM2.5). SO2 emissions from thermal power plants in India are estimated to be approximately 4,327 kilotonnes annually, and these plants emit SO2 at levels 240 times greater than stubble burning, a seasonal contributor to air pollution. The high levels of SO2 emissions are due to the lack of flue gas desulfurisation (FGD) systems installed in these power plants. FGD systems can reduce SO2 emissions by up to 64%, and full implementation of these systems could significantly reduce India's air pollution problem.

In addition to SO2, thermal power plants also emit large amounts of PM2.5, which are very fine, toxic pollutants released during the combustion of fuels. These particles contribute to respiratory and cardiovascular diseases and have been linked to a growing number of asthma cases and premature deaths in India. The total premature mortality attributable to pollution from coal power plants is expected to increase by 2–3 times annually by 2030.

Despite the severe health and environmental impacts of thermal power plants, there has been a lack of enforcement of emission standards and regulations in India. The country introduced compliance norms for emissions from thermal power plants in 2015, but the deadlines for installing FGD systems have been repeatedly revised and extended. As of 2024, only a small number of power plants near highly polluted areas have complied with the FGD installation requirements.

The Indian government has implemented some initiatives to address air pollution, such as the National Clean Air Programme, which aims to reduce PM2.5 and PM10 concentrations by 20%-30% by 2024. However, more stringent regulatory focus and a multi-faceted approach targeting both seasonal and perennial pollution sources are needed to hold thermal power plants accountable for their emissions and improve air quality in India.

Poor fuel sources

India's air pollution problem is multifaceted and severe, with the country being home to 21 of the world's 30 most polluted cities in 2019. One of the major contributors to this issue is the burning of wood, dung, and other biomass for cooking and heating, particularly in rural areas. This practice, which occurs in over 100 million households, releases carbon-containing gases that are far more reactive than those produced by cleaner fuels. The burning of biomass and fuelwood is the primary reason for the near-permanent haze observed over India in satellite images.

The use of chulhas, traditional cookstoves, has been linked to 300,000 to 400,000 deaths from indoor air pollution and carbon monoxide poisoning. Additionally, the Asian brown cloud, a layer of air pollution that delays the start of the monsoon season, is largely attributed to the burning of biomass. While electricity or clean-burning fuel could provide an alternative, their adoption is hindered by availability and affordability issues.

Another factor contributing to India's poor air quality is the use of adulterated fuel blends in vehicles. The addition of cheaper hydrocarbons to highly taxed fuels like gasoline results in increased emissions of harmful pollutants. Kerosene, for instance, burns less efficiently than gasoline, leading to higher emissions of hydrocarbons, carbon monoxide, and particulate matter. Furthermore, kerosene's higher sulfur content is also a concern.

Traffic congestion, caused by a growing number of vehicles and inadequate infrastructure, exacerbates the problem. Low average trip speeds cause vehicles to burn fuel inefficiently and pollute more per trip. This inefficiency is further compounded by the use of lower-quality fuels.

The combination of poor fuel sources and other factors has severe consequences for public health and the economy. Air pollution contributes to the premature deaths of approximately 2 million Indians annually and causes respiratory and cardiovascular issues. The economic impact is also significant, with an estimated loss of US$28.8 billion in output in 2019 due to worsening air pollution.

Frequently asked questions