Air pollution in India
Air pollution occurs when harmful or excessive quantities of substances including gases, particles, and biological molecules are introduced into the Earth's atmosphere. Air pollution in India is a serious issue, ranking higher than smoking, high blood pressure, child and maternal malnutrition, and risk factors for diabetes. At least 140 million people breathe air 10 times or more over the WHO safe limit  and 13 of the world's 20 cities with the highest annual levels of air pollution are in India.  Air pollution contributes to the premature deaths of 2 million Indians every year. In urban areas, most emissions come from vehicles and industry, whereas in rural areas, much of the pollution stems from biomass burning for cooking and keeping warm. In autumn and winter months, large scale crop residue burning in agriculture fields – a low cost alternative to mechanical tilling – is a major source of smoke, smog and particulate pollution. India has a low per capita emissions of greenhouse gases but the country as a whole is the third largest after China and the United States. A 2013 study on non-smokers has found that Indians have 30% lower lung function compared to Europeans.
The Air (Prevention and Control of Pollution) Act was passed in 1981 to regulate air pollution and there have been some measurable improvements. However, the 2016 Environmental Performance Index ranked India 141 out of 180 countries.
In 2015, Government of India, together with IIT Kanpur launched the National Air Quality Index. In 2019, India launched 'The National Clean Air Programme' with tentative national target of 20%-30% reduction in PM2.5 and PM10 concentrations by 2024, considering 2017 as the base year for comparison. It will be rolled out in 102 cities that are considered to have air quality worse than the National Ambient Air Quality Standards.
Fuel and biomass burning
Fuel wood and biomass burning is the primary reason for near-permanent haze and smoke observed above rural and urban India, and in satellite pictures of the country. Fuelwood and biomass cakes are used for cooking and general heating needs. These are burnt in cook stoves known as chullah or chulha piece in some parts of India. These cook stoves are present in over 100 million Indian households, and are used two to three times a day, daily. Some reports, including one by the World Health Organization, claim 300,000 to 400,000 people die of indoor air pollution and carbon monoxide poisoning in India because of biomass burning and use of chullahs. The air pollution is also the main cause of the Asian brown cloud which is delaying the start of the monsoon. Burning of biomass and firewood will not stop unless electricity or clean burning fuel and combustion technologies become reliably available and widely adopted in rural and urban India.
India is the world's largest consumer of fuelwood, agricultural waste and biomass for energy purposes. From the most recent available nationwide study, India used 148.7 million tonnes coal replacement worth of fuel-wood and biomass annually for domestic energy use. India's national average annual per capita consumption of fuel wood, agricultural waste and biomass cakes was 206 kilogram coal equivalent. The overall contribution of fuelwood, including sawdust and wood waste, was about 46% of the total, the rest being agri waste and biomass dung cakes. Traditional fuel (fuelwood, crop residue and dung cake) dominates domestic energy use in rural India and accounts for about 90% of the total. In urban areas, this traditional fuel constitutes about 24% of the total. India burns tenfold more fuelwood every year than the United States; the fuelwood quality in India is different from the dry firewood of the United States; and, the Indian stoves in use are less efficient, thereby producing more smoke and air pollutants per kilogram equivalent.
Some Indian taxis and auto-rickshaws run on adulterated fuel blends. Adulteration of gasoline and diesel with lower-priced fuels is common in South Asia, including India. Some adulterants increase emissions of harmful pollutants from vehicles, worsening urban air pollution. Financial incentives arising from differential taxes are generally the primary cause of fuel adulteration. In India and other developing countries, gasoline carries a much higher tax than diesel, which in turn is taxed more than kerosene meant as a cooking fuel, while some solvents and lubricants carry little or no tax.
As fuel prices rise, the public transport driver cuts costs by blending the cheaper hydrocarbon into highly taxed hydrocarbon. The blending may be as much as 20–30 percent. For a low wage driver, the adulteration can yield short term savings that are significant over the month. The consequences to long term air pollution, quality of life and effect on health are simply ignored. Also ignored are the reduced life of vehicle engine and higher maintenance costs, particularly if the taxi, auto-rickshaw or truck is being rented for a daily fee.
Adulterated fuel increases tailpipe emissions of hydrocarbons (HC), carbon monoxide (CO), oxides of nitrogen (NOx) and particulate matter (PM). Air toxin emissions — which fall into the category of unregulated emissions — of primary concern are benzene and polyaromatic hydrocarbons (PAHs), both well known carcinogens. Kerosene is more difficult to burn than gasoline; its addition results in higher levels of HC, CO and PM emissions even from catalyst-equipped cars. The higher sulfur level of kerosene is another issue. Fuel adulteration is essentially an unintended consequence of tax policies and the attempt to control fuel prices, in the name of fairness. Air pollution is the ultimate result. This problem is not unique to India, but prevalent in many developing countries including those outside of south Asia. This problem is largely absent in economies that do not regulate the ability of fuel producers to innovate or price based on market demand.
Traffic congestion is severe in India's cities and towns. Traffic congestion is caused for several reasons, some of which are: increase in number of vehicles per kilometer of available road, a lack of intra-city divided-lane highways and intra-city expressways networks, lack of inter-city expressways, traffic accidents and chaos due to poor enforcement of traffic laws. Complete lack of traffic sense in Indian public is the main reason for the chaos on the roads.
Traffic congestion reduces average traffic speed. At low speeds, scientific studies reveal, vehicles burn fuel inefficiently and pollute more per trip. For example, a study in the United States found that for the same trip, cars consumed more fuel and polluted more if the traffic was congested, than when traffic flowed freely. At average trip speeds between 20 and 40 kilometers per hour, the cars pollutant emission was twice as much as when the average speed was 55 to 75 kilometers per hour. At average trip speeds between 5 and 20 kilometers per hour, the cars pollutant emissions were 4 to 8 times as much as when the average speed was 55 to 70 kilometers per hour. Fuel efficiencies similarly were much worse with traffic congestion.
Traffic gridlock in Delhi and other Indian cities is extreme. The average trip speed on many Indian city roads is less than 20 kilometers per hour; a 10 kilometer trip can take 30 minutes, or more. At such speeds, vehicles in India emit air pollutants 4 to 8 times more than they would with less traffic congestion; Indian vehicles also consume a lot more carbon footprint fuel per trip, than they would if the traffic congestion was less. Emissions of particles and heavy metals increase over time because the growth of the fleet and mileage outpaces the efforts to curb emissions.
Greenhouse gas emissions
India was the third largest emitter of carbon dioxide in 2017 at 6.82% share of CO2 emissions, after China (27.21%) and the United States (14.58%). According to a report by the Global Carbon Project, "“after low growth during 2014 to 2016, fossil CO2 emissions have now risen two years in a row, with a 1.6 per cent rise in 2017 and a projected 2.7 per cent (range 1.8 per cent to 3.7 per cent) rise expected in 2018, reaching a record high of 37.1 (plus or minus 2) billion tonnes of CO2. The peak in global CO2 emissions is not yet in sight.” About 65 percent of India's carbon dioxide emissions in 2009 was from heating, domestic uses and power sector. About 9 percent of India's emissions were from transportation (cars, trains, two wheelers, aeroplanes, others). India's coal-fired, oil-fired and natural gas-fired thermal power plants are inefficient and offer significant potential for CO2 emission reduction through better technology. Compared to the average emissions from coal-fired, oil-fired and natural gas-fired thermal power plants in European Union (EU-27) countries, India's thermal power plants emit 50 to 120 percent more CO2 per kWh produced. This is in significant part to inefficient thermal power plants installed in India prior to its economic liberalisation in the 1990s.
Health costs of air pollution
One of the most important reasons for concern for the growing air pollution in the country is its effects on the health of individuals. Exposure to particulate matter for a long time can lead to respiratory and cardiovascular diseases such as asthma, bronchitis, lung cancer and heart attacks. The Global Burden of Disease Study for 2010, published in 2013, had found that outdoor air pollution was the fifth-largest killer in India and around 620,000 early deaths occurred from air pollution-related diseases in 2010. According to a WHO study, 13 of the 20 most-polluted cities in the world are in India; however, the accuracy and methodology of the WHO study was questioned by the Government of India.
Over a million Indians die prematurely every year due to air pollution, according to the non-profit Health Effects Institute. Over two million children -- half the children in Delhi -- have abnormalities in their lung function, according to the Delhi Heart and Lung Institute. Over the past decade air pollution has increased in India significant. Aasthma is the most common health problem faced by Indians and it accounts for more than half of the health issues caused by air pollution.
According to the WHO, India has14 out of the 15 most polluted cities in the world in terms of PM 2.5 concentrations. Other Indian cities that registered very high levels of PM2.5 pollutants are Delhi, Patna, Agra, Muzzaffarpur, Srinagar, Gurgaon, Jaipur, Patiala and Jodhpur, followed by Ali Subah Al-Salem in Kuwait and a few cities in China and Mongolia. 
Air Quality Index (AQI) is a number used to communicate the level of pollution in the air and it essentially tells you the level of pollution in the air in a given city on a given day. The AQI of Delhi was placed under the "severe-plus category" when it touched 574, by the System of Air Quality and Weather Forecasting And Research. In May 2014 the World Health Organisation announced New Delhi as the most polluted city in the world. In November 2016, the Great smog of Delhi was an environmental event which saw New Delhi and adjoining areas in a dense blanket of smog, which was the worst in 17 years.
India's Central Pollution Control Board now routinely monitors four air pollutants namely sulphur dioxide (SO2), oxides of nitrogen (NOx), suspended particulate matter (SPM) and respirable particulate matter (PM10). These are target air pollutants for regular monitoring at 308 operating stations in 115 cities/towns in 25 states and 4 Union Territories of India. The monitoring of meteorological parameters such as wind speed and direction, relative humidity and temperature has also been integrated with the monitoring of air quality. The monitoring of these pollutants is carried out for 24 hours (4-hourly sampling for gaseous pollutants and 8-hourly sampling for particulate matter) with a frequency of twice a week, to yield 104 observations in a year.
The key findings of India's central pollution control board are:
- Most Indian cities continue to violate India's and world air quality PM10 targets. Respirable particulate matter pollution remains a key challenge for India. Despite the general non-attainment, some cities showed far more improvement than others. A decreasing trend has been observed in PM10 levels in cities like Solapur and Ahmedabad over the last few years. This improvement may be due to local measures taken to reduce sulphur in diesel and stringent enforcement by the government.
- A decreasing trend has been observed in sulphur dioxide levels in residential areas of many cities such as Delhi, Mumbai, Lucknow, Bhopal during last few years. The decreasing trend in sulphur dioxide levels may be due to recently introduced clean fuel standards, and the increasing use of LPG as domestic fuel instead of coal or fuelwood, and the use of CNG instead of diesel in certain vehicles.
- A decreasing trend has been observed in nitrogen dioxide levels in residential areas of some cities such as Bhopal and Solapur during last few years. The decreasing trend in sulphur dioxide levels may be due to recently introduced vehicle emission standards, and the increasing use of LPG as domestic fuel instead of coal or fuelwood.
- Most Indian cities greatly exceed acceptable levels of suspended particulate matter. This may be because of refuse and biomass burning, vehicles, power plant emissions, industrial sources.
- The Indian air quality monitoring stations reported lower levels of PM10 and suspended particulate matter during monsoon months possibly due to wet deposition and air scrubbing by rainfall. Higher levels of particulates were observed during winter months possibly due to lower mixing heights and more calm conditions. In other words, India's air quality worsens in winter months, and improves with the onset of monsoon season.
- The average annual SOx and NOx emissions level and periodic violations in industrial areas of India were significantly and surprisingly lower than the emission and violations in residential areas of India
- Of the four major Indian cities, air pollution was consistently worse in Delhi, every year over 5-year period (2004–2018). Kolkata was a close second, followed by Mumbai. Chennai air pollution was least of the four.
Steps Taken/ Policy Recommendations
- The government in Delhi launched an Odd-Even Rule in November, 2017 which is based on the Odd-Even rationing method: This meant that cars running with number plates ending in Odd digits could only be driven on certain days of the week, while the Even digit cars could be driven on the remaining days of the week.
- Local governments of various states also implemented measures such as tighter vehicle emissions’ norms, higher penalties for burning rubbish and better control of road dust
- The Indian government has committed to a 50% reduction in households using solid fuel for cooking
- Some goals set for future are:
- Clean up the transportation sector by introducing 1,000 electric public transport buses to its 5,50-string feet
- Meet a goal of 25% of private vehicles to be electric by 2023
- Provide farmers with a machine called a Happy Seeder which converts agricultural residue to fertilizer
- Analyze health data and study the efficiency of different room filtration systems in areas where indoor air pollution is highest
- Identify effective ways to inform the public about air pollution data
- Launch new citizen science programs to better document exposures
- Reduce Carbon Emissions: "According to Inter-governmental Panel on Climate Change, to limit warming well below 2 degree Celsius, CO2 emissions should decline by about 20 per cent by 2030 and reach net zero around 2075; to limit warming below 1.5 degree Celsius, CO2 emissions should decline by 50 per cent by 2030 and reach net zero by around 2050…"
- Air quality in Delhi
- List of Kerala cities by ambient air quality
- Petroleum coke
- List of most-polluted cities
- Criteria air pollutants
- "State of global air 2019". Retrieved 29 April 2019.
- "Dirty air: how India became the most polluted country on earth". ig.ft.com. Retrieved 2019-03-04.
- "India's air pollution, health burden get NIEHS attention (Environmental Factor, September 2018)". National Institute of Environmental Health Sciences. Retrieved 2019-03-04.
- Badarinath, K. V. S., Kumar Kharol, S., & Rani Sharma, A. (2009), Long-range transport of aerosols from agriculture crop residue burning in Indo-Gangetic Plains—a study using LIDAR, ground measurements and satellite data. Journal of Atmospheric and Solar-Terrestrial Physics, 71(1), 112–120
- Agricultural Fires in India NASA, United States (2012)
- Bob Weinhold , Fields and Forests in Flames: Vegetation Smoke and Human Health, National Institutes of Health
- "CO2 EMISSIONS FROM FUEL COMBUSTION HIGHLIGHTS, 2011 Edition" (PDF). International Energy Agency, France. 2011.
- "Indians have 30% weaker lungs than Europeans". Times of India. Sep 2, 2013.
- "Data : India – Environmental Performance Index – Development". Yale University. 2016. Retrieved 8 April 2016.
- "National Clean Air Programme". 2019. Retrieved 18 January 2019.
- "Green stoves to replace chullahs". The Times of India. December 3, 2009.
- Devendra Pandey (2002). Fuelwood Studies in India: Myth and Reality (PDF). Center for International Forestry Research. ISBN 979-8764-92-7.
- "Urban Air Pollution, Catching gasoline ad diesel adulteration" (PDF). The World Bank. 2002.
- Matthew Barth; Kanok Boriboonsomsin (November 2009). "Real-World CO2 Impacts of Traffic Congestion". Transportation Research Record: Journal of the Transportation Research Board. 2058: 163–171. doi:10.3141/2058-20. Archived from the original on 2016-05-30.
- "Gridlocked Delhi: six years of career lost in traffic jams". India Today. September 5, 2010.
- R. Kumari; A.K. Attri; L. Int Panis; B.R. Gurjar (April 2013). "Emission estimates of Particulate Matter and Heavy Metals from Mobile sources in Delhi (India)". J. Environ. Science & Engg. 55 (2): 127–142.
- "50% Bangalore kids hit by asthma". The Times Of India. 6 November 2007.
- "CO2 emissions by country 2017". Statista. Retrieved 2019-03-13.
- "India drives global rise in CO2 emissions: Report". The Indian Express. 2018-12-06. Retrieved 2019-03-13.
- Tammy Webber; Katy Daigle. "US exporting dirty fuel to pollution-choked India". San Jose Mercury-News. Bay Area News Group. AP. p. A4.
- "India tops world in bad air quality: Kanpur, Delhi among 15 worst cities, Mumbai 4th most polluted megacity - Times of India". The Times of India. Retrieved 2019-03-09.
- DelhiNovember 8, India Today Web Desk New; November 8, 2018UPDATED:; Ist, 2018 13:05. "Delhi records worst air quality of year after rampantly bursting crackers". India Today. Retrieved 2019-03-13.
- Madhok, Madhok (16 October 2014). "Here is why India has no clue how bad its air pollution problem is". Quartz India. Retrieved December 4, 2015.
- "New Delhi's Air Pollution Went Off the Scale This Week". 15 June 2018.
- "NATIONAL AIR QUALITY MONITORING PROGRAMME". Ministry of Environment & Forests, Government of India. 2011.
- "Odd-Even Rule: 5 Things You Need to Know - NDTV CarAndBike". CarAndBike. Retrieved 2019-03-13.
- "WHO | India takes steps to curb air pollution". WHO. Retrieved 2019-03-13.
- "Searching for solutions to Delhi's air pollution problem". Chemical & Engineering News. Retrieved 2019-03-09.
- Sengupta, Ramprasad; Mandal, Subrata. "Health Damage Cost of Automotive Air Pollution : Cost Benefit Analysis of Fuel Quality Upgradation for Indian Cities" (PDF). Retrieved 22 July 2014.
- Cropper, Maureen (June 2012). "The Health Effects of Coal Electricity Generation in India" (PDF). Retrieved 22 July 2014.