Air Pollution - The Supreme Court-appointed Environment Pollution (Prevention and Control) Authority recently declared a public health emergency in Delhi-NCR, banning construction activity till November 5.

What is ‘Severe+’ or ‘Emergency’ Level of Air Pollution?

  • Air pollution is said to reach emergency levels when PM2.5 levels cross 300 µg/m3 or PM10 levels cross 500 µg/m3. 
  • As per the Graded Response Action plan (GRAP), these levels – which are about five times the standard – need to persist for 48 hours or more before an emergency level can be declared.

EPCA Environment Pollution (Prevention and Control) Authority is Supreme Court mandated body under Environment Protection Act, 1986, mandated to enforce the Graded Response Action Plan (GRAP) in NCR as per the pollution levels.


About Air Pollution

Air pollution can be defined as the presence of any solid, liquid or gas, including noise and radioactive radiation in the atmosphere in such a concentration that can be directly or indirectly harmful to man or other living organisms, plants, property, or interfere with the normal ecological processes. 

Sources of Air Pollution:

These are the burning of coal and coke, industrial emissions, Commercial activities, thermal power generation units. Transportation is a major source of pollution causing the highest pollution in metropolitan cities in developing countries. 

Climate change is making the effects of air pollution worse by changing atmospheric conditions and amplifying forest fires.

Classification of Pollutants

  • Primary air pollutants - Materials that when released pose health risks in their unmodified forms or those emitted directly from identifiable sources. Primary Air Pollutants are

-Carbon monoxide

-Sulfur dioxide

-Nitrogen oxides


-Particulate matter

  • Secondary air pollutants - Primary pollutants interact with one another, sunlight, or natural gases to produce new, harmful compounds. Secondary Pollutants are:
    • Ozone
    • PAN (peroxyacetyl nitrate)
    • Photochemical smog
    • Aerosols and mists (H2SO4)

 About Particulate pollutants

  • Particulate matter," also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. 

Particle pollution includes:

  • PM10: inhalable particles, with diameters that are generally 10 micrometers and smaller; and found near roadways and dusty industries.
  • PM2.5: fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.

Effects of air pollution:

In addition to human lives lost, there's an estimated global cost of 225 billion dollars in lost labor and trillions in medical costs.

Health effects:

Some particles less than 10 micrometers in diameter can get deep into your lungs and some may even get into the bloodstream. Of these, particles less than 2.5 micrometers in diameter, also known as fine particles or PM2.5, pose the greatest risk to health.

Acid rain:

Different oxides of nitrogen and sulfur in the atmosphere react with the water vapor present in the atmosphere to form sulphuric acid and nitric acid. The acids drop down with rain, making the rain acidic. 

Ozone depletion:

Chlorofluorocarbons (CFCs) which are used in refrigerators, air conditioners and pressuring agents in aerosol sprays which damage the ozone layer of the atmosphere.


It is the presence of high levels of all these SPM causes visibility to be lowered, especially in cold weather when water condenses out of the air. 

Air pollution in India

  • As per WHO State of global air/2019 report, PM2.5 pollution contributed to nearly 3 million early deaths in 2017. More than half of this disease burden fell on people living in China and India. 
  • A new study by IQAir AirVisual and Greenpeace has identified that seven of the worst 10 cities and 22 of the worst 30 are Indian cities.
  • As for India’s sudden rise in the rankings, a big factor is that pollution in many of these cities is being measured and reported for the first time.

Reasons for air pollution in Delhi

  1. Meteorological Condition- During winters, high-pressure systems, develops over Delhi which makes air still which allows pollution levels to build up.
  2. Delhi as a bowl-  As winds arrive from the coasts, bringing with them pollutants picked up along the way, they get ‘trapped’ right before the Himalayas. 
  3. Vehicular Pollutants - As per the report published in 2018 by The Energy and Resources Institute (Teri) vehicle pollution is the cause of 28 percent of PM2.5 emissions and 24 percent of PM 10 pollution.
  4. Agricultural Pollutant- The share of stubble burning in Delhi’s pollution has increased to 46% resulting in the current high particulate matter concentration.
  5. Industrial Pollutants- The north-westerly winds that come into Delhi transport sulfur dioxide (SO2) emitted from large power plants and refineries. There are thirteen power plants that run on fossil fuels in a 300km radius of the capital.
  6. Other causes like household pollutants include wood-burning fires, fires on landfill sites, exhaust from diesel generators, dust from construction sites, burning garbage and illegal industrial activities in Delhi.

Stubble burning is the practice of burning off the residual crop mainly paddy before the sowing of rabi crops in the northern part of India (Punjab and Haryana) in order to make the soil more fertile and clearing the land.

  • Judicial intervention: National Green Tribunal fixed the environment penalties at Rs. 2,500 per incident of stubble burning.
  • Govt. initiatives: Punjab govt. helps farmers to buy subsidized equipment such as Happy Seeder, Paddy Straw Chopper/Cutter, Mulcher, RMB Plough, Shrub Cutter, Zero Till Drill, Super Straw Management System on Combine Harvesters, Rotary Slasher and Rotavator.


  • The rice-wheat rotation: Extensive development of irrigation, assured price (minimum support price) and secured market (government procurement) have induced farmers to grow paddy resulting in depletion of soil nutrients, the decline in the water table, the build-up of pests and diseases, and micronutrient deficiency.
  • No alternatives: Rice straw is not used as fodder as it is found to be non-palatable to animals due to its high silica content so farmers are prompted to burn it on the field instead of incurring a high cost of collecting it.
  • Faulty machines: The combine harvester machine leaves the residues in such a state that it is difficult to collect them manually.
  • Crop diversification with vegetables and fruits hit a roadblock due to marketing problems.
  • Ignoring biomass energy: Punjab and Haryana have not made much progress in creating biomass-based power generation plants.

Possible solutions:

  • Initiatives can also be made to convert the removed residues into enriched organic manure through composting.
  • Compensating farmers 
  • Crop diversification with vegetables and fruits
  • Promoting the use of various techniques such as Happy Seeder machine, Combine Harvester
  • Incentivising biomass-based power plants in Punjab and Haryana 
  • Promoting industrial use of stubble — such as extraction of yeast protein — can be explored through scientific research.

Legislations for checking air pollution

  1. The Air (Prevention and Control of Pollution) Act of 1981: The Air Act expanded the authority of the central and state boards established under the Water Act, to include air pollution control.
  2. The Environment (Protection) Act,1986 (Air Act): It provides a framework for the coordination of central and state authorities established under the Water Act,1974 and Air Act,1981.

Govt. initiatives for checking air pollution

  • Graded Response Action Plan in NCR region: These actions are part of a series of incremental steps to be taken under the Graded Response Action Plan (GRAP) as the quality of the air deteriorates, for example, Odd-Even system for vehicles.
  • The National Air Quality Index (AQI) 
    • AQI transforms complex air quality data of various pollutants into a single number (index value), nomenclature and color. 
    • The AQ sub-index and health breakpoints are evolved for eight pollutants (PM10, PM2.5, NO2, SO2, CO, O3, NH3, and Lead (Pb)) 
  • National Clean Air Programme: NCAP aims to cut concentrations of PM2.5 and PM10 (larger particulate matter) throughout the country between 20-30 percent by 2024
  • National Air Quality Monitoring Programme: Under NAMP, four air pollutants viz. SO2, NO2, suspended particulate matter (PM10), and fine particulate matter (PM2.5) have been identified for regular monitoring at all the locations
  • National Ambient Air Quality Standards (NAAQS): NAAQs are the standards for ambient air quality with reference to variously identified pollutants notified by the CPCB under the Air (Prevention and Control of Pollution) Act, 1981. 
  • Forty-Two Action Plan: The CPCB has issued a comprehensive set of directions under the Air (Prevention and Control of Pollution) Act, 1986, for the implementation of 42 measures to mitigate air pollution in the major cities, including Delhi and NCR.
  • Pradhan Mantri Ujjwala Yojana (PMUY) for shifting away from biomass fuels, with a focus on women as the drivers of change provided LPG connections to 35 million poor families free of charge and aims to provide 80 million connections by 2020. 


  • Reactive approach: The govt. reacts when the problem goes out of hand.
  • Poor governance: lax enforcement of standards for car exhausts, crop burning, or dust from construction sites leads to more particulates in the air.
  • Politics: Rural politicians and urban politicos in India have vastly different constituencies, making it difficult for coordinated action.
  • Toothless Central pollution control board (cpcb) and SPCBs: The nodal agency for overseeing the environmental regulations in the country, has no bona fide powers to enforce the laws; its major function being advisory and providing technical assistance.
    • The state pollution control boards (spcbs) are said to underperform because of inadequate staff for implementation and monitoring.
    • Corruption: The cost of non-compliance is lower than the cost of compliance under the present circumstances -- hence corruption is encouraged by the polluter too.
    • Less autonomy: spcbs are autonomous bodies, but in actual practice, they work under political influence preventing them from taking independent, professional or technical decisions.
  • Large gaps and ambiguities in the legislative framework are leaving the environment at the discretion of a host of ill-informed officials who are not educated in the law.
  • Inadequate public transport: A report submitted by the Environment Pollution (Prevention and Control) Authority to the Supreme Court had said that there is an enormous shortfall in the current level of public transport services. 
  • Private vehicles: Exposure to toxic vehicular pollution has worsened in India due to the staggering pace of motorization.
  • Compliance on the part of the industry: There is a lack of awareness of the applicable acts and rules on the part of industries. 
  • Small scale industries: India has more than three million ssis that contribute around 65 percent of the total industrial pollution load in the country. The fear of reduced profits inhibits the SSI operators from investing in pollution control equipment.
  • Unplanned urbanization: Poor air and water quality, insufficient water availability, waste-disposal problems, and high energy consumption are exacerbated by the increasing population density and demands of urban environments.
  • High dependence on coal: Coal-fired plants generate 72% of India’s electricity. Mining coal causes pollution. Besides CO2, burning coal produces pollutants like mercury, sulfur dioxide, which is linked to acid rain, and particulate matter.
  • Indoor air pollution and poverty: Two-thirds of India’s population still lives outside of cities, and 80 percent of these poor households rely on biomass like wood and dung for cooking and heating. This also causes pollution indoors, which is especially dangerous for children, according to the WHO. 
  • Lack of data: Assessment of environmental impacts of air pollution has not been done because of a lack of data and funding.

Way forward:

Cleaner fuels for motorized transport, removing subsidies on dirty fuels, enforcing strict controls on open waste burning and reducing industrial emissions.

Best practices:

  • In 2013 China adopted measures to control coal-fired boilers, provide cleaner domestic fuels, and industrial restructuring.
  • By the end of 2017 fine particulate pollution (PM2.5) had fallen by 35 percent and by 25 percent in the surrounding Beijing-Tianjin-Hebei region.
  • Recruiting technocrats: Pollution control regulation and monitoring requires a degree of technical expertise. 
  • SSI sector: Only clean industries must be encouraged in this sector.
  • Improving public transport: There is a  need for massive augmentation of public transport so that people do not use their cars.
  • Strong city planning: Regulating the form of urbanization prevalent in many of our cities to promote smaller, more compact cities.
  • Involving the local community and local government in anti-pollution drives.
  • Need a sweeping government effort to shift more households to liquefied petroleum gas (LPG) instead of biomass fuels.
  • Create private-public partnerships to provide services such as waste disposal and housing.
  • Plant trees and incorporate the care of city green spaces as a key element in urban planning.
  • Renewable energy: Emissions from electrical power generation should be controlled. Renewable energy should be promoted.
  • Motor vehicle emissions: controlled emissions of VOCs and use of catalytic converters, engine redesign, and fuel reformulation to minimize evaporation and optimize the performance of emission controls should be promoted. BS-VI mass emission standards should be strictly enforced by April 2020.
    • Bureau of Indian Standards (BIS) norms for upgraded fuels, sulfur content is reduced to 10 mg/kg max in BS-VI from 50 mg/kg under BS-IV. This key reduction in sulfur makes it possible to equip vehicles with better catalytic converters that capture pollutants.
    • Running auto-rickshaws and taxis on clean fuels like compressed natural gas (CNG).