New Delhi: Experts Wednesday stressed on the need to focus on revising India's air quality standards to make them more stringent as the WHO released new guidelines and warned that air pollution is one of the biggest environmental threats.
IIT-Kanpur professor S N Tripathi, who is also a member of the Steering Committee of National Clean Air Programme (NCAP), said air pollution is a severe health crisis and the World Health Organization's revised guidelines bring the issue under focus.
"There is a body of scientific evidence to prove that air pollution is leading to severe health impacts and 90 per cent of the entire global population is breathing polluted air," he said.
"There are no two ways about the need for revising India's air quality standards to make them more stringent," he said.
Sharing a similar view, Ravindra Khaiwal, Professor, Environment Health, Post Graduate Institute of Medical Education and Research, Chandigarh, said these stringent WHO standards for key air pollutants are important and swift action is needed to improve the air quality.
"The WHO has recommended more stringent standards for key air pollutants, e.g., PM2.5 norms for 24 hrs average will be 15 µg/m3 instead of 25 µg/m3. This is important and would bring the focus on strict & swift action for better air quality. Air pollution has become a major risk factor for premature mortality and morbidity.
Meeting the new WHO Global Air Quality Guidelines seems a challenge, but under National Clean Air Program (NCAP), India is committed to minimise 20-30 per cent of cities' air pollution, he said.
"Collective efforts are needed to mitigate the air pollution and gain in terms of better human health and climate.”
The guidelines recommend new air quality levels to protect the health of populations by reducing levels of key air pollutants, some of which also contribute to climate change.
WHO's new guidelines recommend air quality levels for six pollutants -- particulate matter (PM) 2.5 and PM 10, ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO).
The 2021 guideline stipulates that PM 10 should not exceed 15 µg/m3 (micrograms per cubic metre of air) annual mean, or 45 µg/m3 24-hour mean. As per the 2005 guideline, the limit was 20 µg/m3 annual mean or 50 µg/m3 24-hour mean for PM 10.
It recommends that PM 2.5 should not exceed 5 µg/m3 (micrograms per cubic metre of air) annual mean, or 15 µg/m3 24-hour mean. As per the 2005 guideline, the limit was 10 µg/m3 annual mean or 25 µg/m3 24-hour mean for PM 2.5.
As per the 2005 guideline, the AQG level of another pollutant Nitrogen Dioxide was 40 µg/m3 annual mean which has now been changed by the WHO to 10 µg/m3.
AQG is an annual mean concentration guideline for particulate matter and other pollutants.
Khaiwal said that most Indian cities failed to meet even the 2005 guidelines and stressed on the need to strengthen health data and revise the National Ambient Air Quality Standards (NAQS) accordingly.
"Raw health data is required to conduct a large range of health studies vis-a-vis air pollution impacts for India's varied demography, exposure and differing PM2.5 composition. A single exposure prevention response will not suit the Indian population," he said.
According to Greenpeace India, among 100 global cities, Delhi's annual PM2.5 trends in 2020 was 16.8 times more than WHO's revised air quality guidelines of 5 ug/m3, while Mumbai's exceeded eight-fold, Kolkata 9.4 times, Chennai 5.4 times, Hyderabad seven-fold and Ahmedabad exceeded 9.8 times.
Sunil Dahiya, Analyst, Centre for Research on Energy and Clean Air (CREA), said it has been more than a decade since India notified its NAQS in 2009 and it was time to make use of the evidence gathered by the WHO about the severe health impacts of air pollution.
"The good thing is that India is already working on revising the standards, we just need to make sure we make use of evidence gathered by WHO and others on increasing and severe health impacts of pollutants at lower levels and try to aim towards moving closer to WHO prescribed levels for pollutants," he said.
According to Arun Sharma, Director, National Institute for Implementation Research of Non-Communicable Diseases, ICMR, it is a huge challenge for India to meet these guidelines.
'Nonetheless, I hope that efforts by all stakeholders will be intensified so as to make honest efforts to aim towards the revised levels," Sharma said.
The health risks associated with particulate matter equal or smaller than 10 and 2.5 microns (µm) in diameter (PM10 and PM2.5, respectively) are of particular public health relevance, the WHO said, adding that both these pollutants are capable of penetrating deep into the lungs but PM2.5 can even enter the bloodstream, primarily resulting in cardiovascular and respiratory impacts, and also affecting other organs.
Particulate matters are primarily generated by fuel combustion in different sectors, including transport, energy, households, industry, and from agriculture.
The WHO said that adhering to the new AQGs could save millions of lives. PTI