Air is mainly contaminated (or polluted) by fine particulate matter (PM2.5), ozone, and oxides of sulphur and nitrogen. In recent years, air pollution has become a very serious problem, the world over.
Threat to Human Health
Air pollution is one of the biggest and most immediate environmental threats to human health. It results in millions of premature deaths each year and the loss of millions more healthy years of life. It has been linked to a range of adverse health effects, including cardiovascular and respiratory disease, cancer, neurological effects, and birth outcomes. Moreover, air pollution also involves enormous economic losses.
Particulate Matter
Particulate matter (PM) consists of microscopically small solid particles or liquid droplets that can either be emitted directly into the air, or formed from secondary reactions involving gaseous pollutants that combine in the atmosphere. It can include sulphates, nitrates, ammonia, sodium chloride, black carbon, mineral dust, and water. The main concern is the health risks associated with PM equal to or smaller than 10 micrometres (or microns) and 2.5 micrometres in diameter—known as PM 10 and PM 2.5, respectively, and referred to as ‘coarse’. Sources of coarse particles include crushing or grinding operations, and dust from paved or unpaved roads. Other particles may be formed in the air from the chemical change of gases. They are indirectly formed when gases from burning fuels react with sunlight and water vapour. These can result from fuel combustion in motor vehicles, at power plants, and in other industrial processes.
Though PM2.5 as well as PM10 are capable of penetrating deep into the lungs, PM2.5 can even enter the bloodstream, the result being cardiovascular and respiratory problems and also impacts on other organs. PM2.5, also called ‘fine particulates’, can only be seen with an electron microscope. Fine particles are produced from all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes.
In general, the smaller and lighter a particle is, the longer will it stay in the air. Larger particles (greater than 10 microns in diameter) tend to settle to the ground by gravity in a matter of hours whereas the smallest particles (less than 1 micron) can stay in the atmosphere for weeks and are mostly removed by precipitation.
The report of the Lancet Commission on pollution and health, released in May 2022, highlights the seriousness of the problem and the fact that much remains to be done on this issue. As per the report, pollution was responsible for 9 million premature deaths in 2015, making it the world’s largest environmental risk factor for disease and premature death. The reductions in the number of deaths ascribable to the types of pollution associated with extreme poverty (household air pollution and water pollution) are nullified by increase in deaths due to ambient air pollution and toxic chemical pollution (lead). Deaths due to these modern pollution risk factors have increased by 7 per cent since 2015 and by over 66 per cent since 2000. More than 90 per cent of pollution-related deaths take place in low-income and middle-income countries.
Outdoor air pollution as a whole, especially the particulate matter (PM), which refers to fine particles in the air, was declared as class-1 cancer-causing agent (carcinogen) in 2013 by the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO). Air pollution, reportedly, leads to over 6·5 million deaths each year globally, and this number is increasing.
Economic Implications
The Lancet report estimated the present value of future output lost when a person dies prematurely due to pollution in six regions, including India, China, Ethiopia, Nigeria, the US, and EU-15. It said that in the year 2000, India lost output equivalent to 3.2 per cent of its GDP as a result of pollution. Further, the study notes that economic losses due to modern forms of pollution have increased as a proportion of GDP between 2000 and 2019 in India, China, and Nigeria, and are now estimated to amount to about 1 per cent of GDP in each of these countries. The global cost of fossil fuel air pollution is estimated to be about US$ 8 billion per day.
Air Pollution Situation in India
India remains one of the worst affected countries when it comes to air pollution. As per the Lancet report, in 93 per cent of India the amount of pollution remains well above the WHO guidelines. India had the largest estimated number of pollution-related deaths in 2019.
As per WHO (2016) estimates, 10 out of the 20 most populated cities in the world are in India. Based on the concentrations of PM2.5 emissions, India was ranked the fifth most polluted country by WHO (2019), with 21 among the top 30 polluted cities being in India.
According to the World Air Quality Report released in March 2022 by IQAir, a Swiss firm, India was the fifth most polluted country among 117 countries, regions and territories around the world that were assessed. The annual average PM2.5 levels in the country reached 58.1 micrograms per cubic metre in 2021, making a return to pre-quarantine (for COVID 19) concentrations measured in 2019. Of the 15 most polluted cities in Central and South Asia, 10 were in India, and Bhiwadi in Rajasthan was the most polluted city in the world. (The data, incidentally, is the first major global air quality report based on the WHO’s updated annual air quality guidelines for PM2.5.)
In a study commissioned by the Central Pollution Control Board, scientists from India’s top cancer institutes tracked 11,000 schoolchildren in Delhi and other cities for three years. They found that particulate pollution had likely caused irreversible reduction in the children’s lung function.
Geographical Aspects Contributing to Increased Air Pollution
While the increase in population and human activities, especially the burning of solid fuels in households and increased vehicular traffic, are major contributors to air pollution, the air quality of any area also depends on local and regional weather patterns and, to some extent, the topography of the region. Due to increased buoyancy and efficient ventilation in summer, pollution waves rise to the free atmosphere, resulting in a reduced level of surface level PM2.5 concentration in the region. In winter, in a phenomenon called ‘winter inversion’, the cooler air near the Earth’s surface, being dense, is trapped under the warm air above that forms a kind of atmospheric ‘lid’. As the vertical mixing of air happens only within this layer, in winter the pollutants released lack enough space to disperse in the atmosphere. Cold winter air means that the pollution stays where we can breathe it instead of rising into the stratosphere, and the damp fog helps capture all the dust from coal fires and vehicle exhausts. The situation in the Gangetic Basin is much worse than that in peninsular India and coastal regions, because of topography. The Himalayas act as a barrier to dissipation of pollution emanating from the cities located in the basin. As a result, cities in this region are more prone to sustained bad air quality. There is also a strong positive relationship between increased pollution levels and occurrence of dense fog episodes.
WHO’s Updated Air Quality Guidelines and India
The WHO came out with an updated version of the global air quality guidelines (AQGs) in 2021, after a long gap (the last update was in 2005). Global air pollution standards have been updated in view of the emerging scientific evidence in the last decade on the much more serious impact of air pollution on health than earlier understood. Not a single country managed to meet the WHO’s air quality standard in 2021.
The main concern is the health risks associated with PM10 and PM2.5 of which PM2.5 is a greater health concern, since smaller particles can travel more deeply into our lungs and cause more harm.
As per the latest WHO guidelines, the annual average for PM10 should not be more than 15 micrograms per cubic metre (µg/m3) of air, while the 24-hour average should not exceed 45 µg/m3. The earlier limit was 20 µg/m3 annually and 50 µg/m3 for 24 hours.
The annual average for PM2.5 is recommended to not exceed 5 µg/m3, and the 24-hour average is not to exceed 15 µg/m3. The earlier limit was 10 µg/m3 annually and 25 µg/m3 for 24 hours.
Other recommendations are: the ozone levels average should not exceed 100 µg/m3 over a 24-hour period, nitrogen oxide should not exceed 25 µg/m3; sulphur dioxide should remain below 40 µg/m3; and carbon monoxide levels should not exceed 4 µg/m3 over the same time period.
(Ozone in the air is also a major factor in asthma morbidity and mortality, while nitrogen dioxide and sulphur dioxide also can play a role in the onset of asthma, bronchial symptoms, lung inflammation, and reduced lung function.)
India adopted the National Ambient Air Quality Standards (NAAQS) in 1982 for the first time, and these standards were revised in 1994 and 2009 mentioning eight prime pollutants, namely, PM2.5, PM10, nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, benzene, and ammonia.
NAAQS 2009 specify an annual limit of 60 µg/m3 for PM10 annually and 100 µg/m3 for a 24-hour period, and the limits are 40 for PM2.5 annually and 60 on a 24-hour period. There are also standards for a host of chemical pollutants including sulphur dioxide (50 µg/m3 annual and 80 for 24 hours), nitrogen dioxide (40 µg/m3 annual and 80 for 24 hours). Standards are also specified for ozone, carbon monoxide, lead, and several other pollutants, but the limits are nowhere near those recommended by the WHO.
The Indian government has sanctioned a review of the existing standards and the criteria governing these standards as well as incorporating new parameters in light of the advances in scientific research. With changes in fuel, technology and demographics as well as advances in air pollution measurement techniques, risk and exposure assessment, a review of NAAQS is necessary for improvement in public health. The Central Pollution Control Board (CBCP) has called upon a team of experts led by IIT Kanpur to refresh and update the pollutants’ base. The experts would study the criteria of various countries as well as the WHO guidelines before coming to a conclusion. They will also take into account India’s meteorological and geographical status and factors while making recommendations to update NAAQS.
Efforts to Curb Air Pollution in India
The central government launched the National Clean Air Programme (NCAP) in 2019 as a long-term, time-bound, national level strategy to tackle the air pollution problem across the country in a comprehensive manner. It set targets to achieve 20 per cent to 30 per cent reduction in PM concentrations by 2024 (keeping 2017 as the base year for the comparison) in at least 102 cities. The city-specific action plans include measures for strengthening the monitoring network, reducing vehicular/industrial emissions, increasing public awareness, etc.
India launched the Air Quality Index (AQI) in 2014. It is a tool developed by CPCB in consultation with IIT Kanpur to showcase the status of air quality in a particular location to any person who is interested. It transforms complex air quality data of various pollutants into a single number and colour and categorises quality as Good, Satisfactory, Moderately Polluted, Poor, Very Poor, and Severe. The AQI is based on eight pollutants, namely, PM10, PM2.5, nitrogen dioxide, sulphur dioxide, carbon monoxide, ozone, ammonia, and lead. Air quality information collection and dissemination are done from a centralised location. It provides real-time air quality status to all stakeholders. The Graded Response Action Plan was notified in 2017, for prevention, control and abatement of air pollution in Delhi and the NCR.
The government brought out a comprehensive action plan in 2018 for identifying timelines and implementing agencies for actions identified for prevention, control and mitigation of air pollution in Delhi and NCR.
The SAMEER app has been launched to provide air quality information to the public along with a provision for registering complaints against air polluting activities.
The Environment Education, Awareness and Training Scheme, initiated by the Ministry of Environment, Forests and Climate Change, seeks to spread environmental awareness among all sections of the society and involve people in conservation of environment. Under the National Green Corps (NGC) programme of the ministry, many schools have been identified as eco-clubs, where a large number of students actively participate in various environment protection and conservation activities, including the issues related to the air pollution.
A dedicated media corner has been created, including Twitter and Facebook accounts, for access to air quality related information, which also serves as a platform for the public to lodge complaints, if any.
The CPCB website is used for crowd sourcing of innovative ideas/suggestions/proposals from the public to strengthen efforts for improving air quality in Delhi-NCR. For field feedback on air polluting activities in Delhi and major NCR towns, CPCB teams have been deployed since October 7, 2019.
The government has developed, and continues to develop, guidelines for air quality and ordinances to restrict emissions in an effort to control air pollution. Various initiatives, such as the use of compressed natural gas (CNG) as an alternative less polluting fuel, the introduction of Bharat Stage VI for vehicles and fuel standards, the Pradhan Mantri Ujjwala Yojana (PMUY), and the shift towards expanding renewable energy, are efforts to control air pollution. According to the first independent impact assessment of the PMUY, released in March 2022, greater penetration and usage of LPG as a cooking fuel under the scheme is estimated to have prevented at least 1.5 lakh pollution-related premature deaths in the year 2019.
An effort has been made in some places at door-to-door collection of segregated wastes to tackle the problem of open burning of garbage and household wastes. Compost pits have been established in urban cities. Steps to control the concentrations of PM and dust particles include creating green buffer around cities, maintenance of 33 per cent green cover around urban areas, and installation of water fountains across the cities, among other things.
Efforts have been made to adopt renewable energy on a large scale, for example, 60 per cent of Delhi Metro’s daytime energy requirement is being met through solar power from the 750 MW Rewa Solar Project in Madhya Pradesh, reducing its dependence on coal-based electricity, as well as saving a huge amount on its energy bill over the next 25 years; solar power is being increasingly used in powering hotels and office buildings even in the private sector.
There have been innovations by entrepreneurs that are encouraging. Chakr Innovation brought out the world’s first retro-fit emission control device for diesel generators, capable of capturing nearly 90 per cent of particulate matter emissions from the exhaust air without reducing energy efficiency. The diesel soot captured from the exhaust is converted into inks and paints. ADITYA is India’s first solar ferry. Built by NavAlt Solar & Electric Boats, it brings together innovation in naval design and engineering, solar power, and advanced controls. It is India’s first commercially viable solar-powered ferry which gets over 80 per cent of its energy from the Sun. Agnisumukh manufactures clean and green energy efficient stoves which produce flameless, smokeless, noiseless, and odourless uniform radiant heat through LPG/bio-gas/natural gas. These cooking stoves save 30 per cent on gas and produce no soot, thus helping to beat indoor air pollution in commercial kitchens. Microwaves are now available in the Indian market to treat infectious waste and eliminate air emissions, including toxic persistent organic pollutants (POP) which are chemicals that adversely affect human health and the environment. These and other such products have been commercialised on a fast-track in a joint programme of the United Nations Industrial Development Organization (UNIDO) with the Ministry of Micro, Small and Medium Enterprises, funded by the Global Environment Facility.
The World Bank is supporting India in tackling air pollution under its Country Partnership Framework. The main emphasis is on the Indo-Gangetic Plain where, due to the population density and pollution intensity, there is a great need to support capacity and systems to tackle the challenge. The focus of the framework will be on developing institutional capabilities and implementing systems that are crucial for change.
Strategies to Combat Air Pollution
A combination of effective policies, technologies, and land-use planning could help evolve a control strategy for air pollution mitigation.
Some potential strategies are as follows:
- In Indian cities, the huge increase in private vehicles is a major contributor to air pollution. But norms to set a certain limit to private vehicle ownership can work only if an efficient and adequate public transport system is developed. So, the development of public transport (which should also be non-polluting) has to be given a priority.
- Development of improved facilities for walking, biking, and relocation of point sources out of urban centres could help curb emissions significantly.
- Innovations such as the introduction of hybrid vehicles or fuel cell vehicles or fuel modifications, such as ultra-low sulphur fuels, or alternative fuels like hydrogen fuel in Japan could be of much help in reducing air pollution. In recent years, reduction in sulphur fractions in the fuels, has resulted in decrease in sulphur oxides.
- Emission trading, also known as cap and trade, could be applied in urban cities, as is prevalent in the US, where economic incentives are offered to reduce the pollutant.
- Stricter emission standards, cleaner fuels, advancements in engines, manufacture of cleaner and green vehicles (for example, electric vehicles), and post-emission treatment technologies could cut down pollution levels in urban areas to a considerable extent. Concrete policy measures such as relocation of industries to the outskirts of the city, should be brought.
- Within the industrial sector, some of the measures include the implementation of zig-zag technology for the stack emissions from brick kilns, and online monitoring of discharges through the online continuous emission monitoring systems (OCEMS).
- Electricity production using coal is considered to be among the major contributors to air pollution. A switchover to renewable energy is important as is the use of cleaner fuel.
- Public awareness programmes should be conducted by the government in rural and urban areas to highlight the importance of managing air pollution at source. Various control measures that could be adopted to reduce polluting emissions should be shown. Public awareness could help reduce such practices as open burning of wastes, crop residue burning, use of biomass as a fuel for cooking and burning of plastic and rubber materials during winters.
- Scientific and technological innovations have to be encouraged and financed so that pollution control devices are developed.
- On an individual level, people can contribute to the reduction of air pollution by carpooling or using public transportation, or cycling. Additionally, buying energy-efficient light bulbs and appliances or otherwise reducing electricity use will help.
The need is to adopt a holistic approach amalgamating various strategies that could be beneficial to attain cleaner air quality in Indian cities and ensure a healthier life. An effective and successful emission control strategy should be a combination of successfully applied scientific ideas and technological advancements; should support the economy and be supported by the public.
Challenges in India
Air quality management in megacities is a four-stage process that involves problem identification, formulation of policies, their implementation, and control. The entire process involves complex analysis of extensive data sets for the effective management of air quality standards. But the lack of transparency and unavailability of data is one of the major challenges towards addressing the issues related to air quality.
Most Indian cities lack the technological and infrastructural backing. In a developing country like India, financial constraints in implementation of advanced urban infrastructural changes pose a serious hurdle to air pollution mitigation strategies.
The lack of public awareness and interest in the emission control measures and inefficient traffic management system are major hurdles in tackling air pollution.
The lack of infrastructural facilities, inadequacy of financial resources to implement advanced infrastructural innovations, and the difficulty in relocation of the industries from the urban centres even after mandatory court decisions are challenges.
While the behavioural patterns among people do not make them open or ready to accept the green solutions, financial constraints are also important. Green energy devices are expensive and to expect the poor or even the lower middle income people to spend on them is unrealistic. Subsidies and/or incentives are required here, but the government too lacks the finances required.
Way Forward
Air quality management is a continuous process. It requires sufficient funding and a sustained focus on building capacity in order to be integrated into the capabilities of the government as well as incorporated into the behaviour of businesses and individuals. Accurate data should be available and used transparently so that suitable policies and programmes may be devised and implemented. Various steps taken by the Government of India to control air pollution in Indian cities must be responsibly implemented. Innovations to deal with pollution must be encouraged and financially supported. Above all, public awareness should be built up about the need to control air pollution, for reducing such pollution can have a positive impact on climate change.
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