Context: In its first-ever update since 2005, the World Health Organization (WHO) has tightened global air pollution standards in recognition of the emerging science.

  • The impact of air pollution on health is much more serious than earlier envisaged.

Key Points

  • As per Environmental organisation Greenpeace, the new guidelines meant that among 100 global cities, Delhi’s annual PM2.5 trends in 2020 was 16.8 times more than the WHO’s revised air quality guidelines, while Mumbai’s exceeded eight-fold, Kolkata’s 9.4, Chennai’s 5.4, Hyderabad’s 7 and Ahmedabad’s 9.8.
  • However, the move does not have an immediate effect in India as the National Ambient Air Quality Standards do not meet the WHO’s existing norms.
  • The government has a dedicated National Clean Air Programme that aims for a 20% to 30% reduction in particulate matter concentrations by 2024 in 122 cities, keeping 2017 as the base year for the comparison of concentration.
    • These are cities that do not meet the NAAQS when calculated from 2011 to 2015.
  • Though the move sets the stage for shifts in policy towards evolving stricter standards.
    • As per experts, this will soon become part of policy discussions — much like climate targets to reduce greenhouse gas emissions keep getting stricter over time — and once cities and States are set targets for meeting pollution emission standards, it could lead to overall changes in national standards.
  • The upper limit of annual PM2.5 as per the 2005 standards, which is what countries now follow, is 10 microgram per cubic metre. That has now been revised to five microgram per cubic metre.
    • The 24-hour ceiling used to be 25 microgram but has now dropped to 15.
    • The upper limit of PM10, or particulate matter of size exceeding 10 microgram, is 20 microgram and has now been revised to 15, whereas the 24-hour value has been revised from 50 to 45 microgram.
  • The WHO norms are not binding on any country. 
    • These are only recommended norms considered safe for human health, as assessed by scientific studies. 
    • But bad air quality does affect the international image of a country as a favourable tourist and investment destination.

What does new air quality guidelines mean for India?

  • The new guidelines take into account several scientific studies in recent years that have suggested that air pollution is much more damaging to human health than earlier known. 
    • By WHO’s own estimates, nearly 7 million deaths every year can now be attributed to diseases that are a direct cause of air pollution.
  • The new air quality guidelines mean that nearly entire India would be considered a polluted zone for most of the year. But India is not alone. 
  • By WHO’s own admission, more than 90 per cent of the world’s population lived in areas which did not meet its 2005 pollution standards. 
  • With the norms now being made even more stringent, this proportion would go up.
  • But South Asia, and especially India, continues to remain one of the most polluted areas in the world, with pollutant levels several times higher than recommended levels. 
    • In Delhi, for example, a Greenpeace study found the average concentration of PM2.5 in 2020 to be nearly 17 times higher than the recommended levels. 
    • In Mumbai, pollution levels were eight times higher; 
    • In Kolkata, over nine times higher; and 
    • In Chennai, over five times higher.
  • India’s own national air quality standards are much more lenient, even compared to WHO’s 2005 norms. 
    • For example, the recommended PM2.5 concentration over a 24-hour period is 60 micrograms per cubic metre, compared to 25 micrograms advised by WHO’s 2005 guidelines. 
    • But even these lower standards are hardly met. In the last few years, the government has been working on a plan to reduce air pollution in some cities by 20-30 per cent by 2024 on a 2017 baseline.

India’s NAAQs

  • It was last revised in 2009 — specify an annual limit of 60 microgram per cubic metre for PM10 and 100 for a 24-hour period.
  • Similarly it’s 40 for PM 2.5 annually and 60 on a 24-hour period. There are also standards for a host of chemical pollutants including sulphur dioxide, lead and nitrogen dioxide.
  • Every year, exposure to air pollution is estimated to cause 7 million premature deaths and result in the loss of millions more healthy years of life.

Related Facts

National Ambient Air Quality Standards (NAAQS)

  • The ambient air quality (AAQ) refers to the condition or quality of air surrounding us in the outdoors.
  • National Ambient Air Quality Standards are the standards for ambient air quality set by the Central Pollution Control Board (CPCB) that is applicable nationwide (The CPCB has been conferred the power by the Air (Prevention and Control of Pollution) Act, 1981). 
  • It includes the following pollutants:
    • SO2 (Sulphur dioxide), 
    • NO2 (Nitrogen dioxide), 
    • PM10, PM2.5, 
    • O3 (Ozone), 
    • Pb (Lead), 
    • CO (Carbon monoxide), 
    • NH3 (Ammonia), 
    • Benzene, 
    • Benzo(a)Pyrene (BaP)- particulate phase only, 
    • As (Arsenic), 
    • Ni (Nickel)

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