Air Pollution In India: Which City Suffers Most?

India has some of the world's most air-polluted cities, with 11 of the top 20 cities in 2024. Poor enforcement of air pollution regulations, industrial emissions, vehicle exhaust, and reliance on fossil fuels all contribute to India's severe air pollution. In 2024, Byrnihat, a city in northeastern India, was recorded to have the worst air pollution globally, with Delhi coming in second. This article will explore the Indian city with the worst air pollution and discuss the factors contributing to this issue.

Delhi's air pollution

Delhi, a metropolis of over 30 million people and the capital territory of India, has witnessed severe air pollution in recent years, raising serious health concerns. In 2022, an August survey by the US-based Health Effects Institute found that Delhi had the worst air pollution of any major city globally. The city's poor air quality has irreversibly damaged the lungs of 2.2 million children, with India bearing the highest death rate from chronic respiratory diseases and asthma worldwide, according to the World Health Organization.

Seasonal factors also play a significant role in Delhi's air pollution. Between October and February, the air quality often deteriorates to poor, severe, or hazardous levels due to the burning of effigies during Vijayadashami, the bursting of firecrackers during Diwali, crop stubble burning in nearby states, thermal power plants, road dust, cold weather, and weak wind patterns that trap smog over the city. In November 2023, for instance, 38% of the year's pollution was attributed to stubble burning.

To address the air pollution crisis, various initiatives have been proposed and implemented. The Indian government launched 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 2019 by IIT Bombay and Washington University to study air pollution in India. Another initiative is the proposed Great Green Wall of Aravalli, a 1,600-kilometre-long and 5-kilometre-wide ecological corridor connecting the Aravalli range to the Shivalik hill range, involving the planting of 1.35 billion new native trees over a decade to combat pollution.

Causes of air pollution

India is one of the most polluted countries in the world, with 11 of the top 20 polluted cities in 2024. Byrnihat, a city in northeastern India, recorded the worst air pollution globally in 2024, with Delhi coming in second. Delhi's air pollution is driven by crop burning in nearby states, stagnant cold air, and weak wind patterns that trap and concentrate smog over the city.

There are several causes of air pollution in India, including:

Industrial and Vehicular Emissions: India's air pollution is largely caused by industrial pollution (51%) and vehicle emissions (27%). The use of motor vehicles in Indian cities results in a build-up of local pollution, particularly under stagnant conditions. Traffic congestion, with average trip speeds of less than 20 kilometres per hour, leads to vehicles emitting pollutants 4 to 8 times more than they would with less congestion. In addition, some Indian taxis and auto-rickshaws run on adulterated fuel blends, which increase emissions of harmful pollutants.

Construction: Construction dust and debris are major contributors to particulate air pollution in India. The city of Delhi, for example, is experiencing rapid growth, with a high density of vehicular traffic and over 3,000 to 4,000 factories contributing to air pollution.

Reliance on Fossil Fuels and Thermal Power: India's dependence on fossil fuels and thermal power for electricity is a significant factor in air pollution. Additionally, biomass burning for cooking and heating is prevalent in rural areas, with approximately 76% of households relying on solid biomass, contributing to indoor air pollution and carbon monoxide poisoning.

Crop Burning: About 17% of India's air pollution is attributed to crop burning, which is a significant contributor to Delhi's winter air pollution.

Weak Regulations and Seasonal Weather Patterns: The Air (Prevention and Control of Pollution) Act of 1981 has failed to reduce pollution due to poor enforcement. India's pollution is worsened by weak regulations and seasonal weather patterns, such as cold temperatures that trap pollutants in certain geographic areas.

Health effects of air pollution

India has some of the world's most polluted cities, with 11 of the top 20 most polluted cities in 2024. Byrnihat, a city in northeastern India, recorded the worst air pollution globally in 2024, with a PM2.5 concentration of 128.2 µg/m3—over 25 times higher than the World Health Organization's recommended limit. New Delhi, the capital territory, recorded the second-worst air pollution levels in 2024. The city experiences the worst winter air pollution of any major city, driven by crop burning in nearby states, stagnant cold air, and weak wind patterns that trap and concentrate smog. Other Indian cities that registered very high levels of PM2.5 pollutants include Patna, Agra, Muzaffarpur, Srinagar, Gurgaon, Jaipur, Patiala, and Jodhpur.

The health effects of air pollution in India are profound and far-reaching. According to a Lancet study, air pollution caused approximately 1.67 million deaths in 2019, resulting in an estimated economic loss of $28.8 billion. The ambient air pollution death toll in India is estimated to be even higher, at 670,000 deaths annually, with a particular increase in hospital visits due to respiratory and cardiovascular conditions. The main causes of air pollution in India include the burning of wood and dirty fuels for cooking and heating, thermal power plants, industrial emissions, and vehicle pollution. These sources of pollution lead to a range of health issues, including respiratory and cardiovascular diseases such as asthma, bronchitis, COPD, lung cancer, and heart attacks.

The World Health Organization estimates that 300,000 to 400,000 people die from indoor air pollution and carbon monoxide poisoning in India due to the burning of biomass and the use of chulhas, traditional cookstoves. Over two million children in Delhi, or half of the children in the city, have abnormalities in their lung function, and around 50% of children in Bangalore suffer from asthma. Air pollution also impacts future generations, as it increases the risk of heart disease, diabetes, and respiratory disease for today's children when they become adults and reduces children's IQ.

The Indian government has implemented various 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. The government is also introducing electric public transport buses, upgrading fossil fuel combustion engine vehicles, and encouraging crop diversification. Additionally, the private sector is increasingly engaged in the clean air movement, with businesses like Wipro and Mahindra Group joining the Clean Air Alliance. These efforts are crucial to reducing the devastating health impacts of air pollution on India's population.

Government initiatives to reduce air pollution

India is home to some of the world's most air-polluted cities, with 11 of the top 20 cities in 2024. Brynihat, a city in northeastern India, recorded the worst air pollution globally in 2024, with Delhi coming in second. The country's hazardous levels of air pollution have caused a major public health crisis, with over a million premature deaths occurring annually due to air pollution. Long-term exposure to particulate matter can lead to respiratory and cardiovascular diseases, including asthma, bronchitis, COPD, lung cancer, and heart attacks.

To tackle this crisis, the Indian government has implemented several initiatives and programs to reduce air pollution and improve air quality. Here are some key government initiatives:

The National Clean Air Programme (NCAP):

The National Clean Air Programme, launched in 2019, aims for a 20-30% reduction in PM2.5 and PM10 concentrations by 2024. It focuses on 102 cities with air quality worse than the National Ambient Air Quality Standards. The program promotes city-specific air quality management plans and encourages collaboration across local and national jurisdictions.

The Graded Response Action Plan (GRAP):

The Graded Response Action Plan is activated in response to poor air quality. Stage I of GRAP includes measures such as dust mitigation at construction sites, effective waste management, and regular road cleaning. These steps are crucial during winter months when pollution levels spike due to agricultural burning, auto emissions, and industrial output.

The Great Green Wall of Aravalli:

This initiative involves the planting of 1.35 billion new native trees over a 10-year period to create a 1,600-kilometre-long and 5-kilometre-wide green ecological corridor along the Aravalli range from Gujarat to Delhi, connecting to the Shivalik hill range.

Indo-Gangetic Plain Project:

The World Bank is supporting the Indo-Gangetic Plain states in implementing state and regional airshed plans for cleaner air. The focus is on developing institutional capabilities and implementing systems vital for change, working with the government and stakeholders to bring in local and international experts.

Building Healthy Cities Project:

Funded by USAID, this community-led study in Indore, India, trained local volunteers as clean air guides. These guides maintained and read air sensor data, educated the community, and supported advocacy efforts.

Clean Fuel Standards and Public Transportation:

Several Indian cities have successfully implemented initiatives like introducing cleaner fuel standards and promoting public transportation to reduce vehicular emissions.

Air Quality Monitoring Systems:

India's Central Pollution Control Board routinely monitors key air pollutants, including sulphur dioxide (SO2), oxides of nitrogen (NOx), suspended particulate matter (SPM), and respirable particulate matter (PM10), at 308 stations in 115 cities/towns across 25 states and 4 Union Territories.

Unconventional Approaches:

The government is also exploring unconventional approaches, such as community-led air quality monitoring, green infrastructure initiatives (vertical gardens, green roofs, and urban forests), art and awareness campaigns, mobile health clinics, and innovative clean cooking solutions (solar cookers, biogas stoves).

These initiatives demonstrate the Indian government's commitment to addressing the country's air pollution crisis and improving the health and well-being of its citizens.

Air pollution in other Indian cities

India is home to some of the world's most polluted cities. According to the 2024 World Air Quality Report, 13 of the 20 most polluted cities in the world are in India. The report also states that India is the fifth most polluted country in the world, with an average Air Quality Index (AQI) of 50.6 μg/m3, which is 10 times higher than the World Health Organization's (WHO) annual PM2.5 guideline value of 5 μg/m3.

Delhi, the capital of India, has consistently ranked among the most polluted cities globally. In 2024, it recorded the second-worst air pollution levels, with a PM2.5 concentration of 91.8 μg/m3. The city experiences severe winter air pollution due to crop burning in nearby states, stagnant cold air, and weak wind patterns that trap smog. Other cities in India with very high levels of PM2.5 pollutants include Patna, Agra, Muzaffarpur, Srinagar, Gurgaon, Jaipur, Patiala, and Jodhpur.

Traffic congestion is a significant contributor to air pollution in Indian cities. Low average trip speeds result in vehicles emitting pollutants 4 to 8 times more than they would with less congested traffic. For example, in cities like Bangalore, around 50% of children suffer from asthma, which is linked to the high levels of air pollution. Construction dust and debris are also major contributors to particulate air pollution in India.

Industrial emissions, vehicle exhaust, and reliance on fossil fuels further exacerbate air pollution in Indian cities, worsened by weak regulations and seasonal weather patterns. Despite this, some cities have shown improvement in air quality. For instance, Solapur and Ahmedabad have witnessed decreasing trends in PM10 levels due to local measures to reduce sulphur in diesel and stringent government enforcement. Additionally, cities like Delhi, Mumbai, Lucknow, and Bhopal have seen reductions in sulphur dioxide levels due to the introduction of clean fuel standards and the increasing use of LPG and CNG as alternative fuels.

The Indian government has recognized the severity of air pollution and has taken initiatives to address the issue. In 2019, the National Clean Air Programme was launched, targeting a 20%-30% reduction in PM2.5 and PM10 concentrations by 2024. Other initiatives include the Great Green Wall of Aravalli, a 1,600-kilometre-long ecological corridor aimed at combating pollution by planting native trees.

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