Explained: Why WHO revised guidelines for air quality — its implications for India

WHO has set lower permissible limits for air pollutants as compared to its previous guidelines that were last issued in 2005. The South Asian region is the worst performer in the world when it comes to air quality. What implications does the WHO’s revised guidelines have for India — details here.

Gaon Connection
| Updated: Last updated on October 1st, 2021,

WHO stated that since the last 2005 global update on air pollutants, there has been a marked increase of evidence that shows how air pollution affects different aspects of health.

Taking cognisance of the health risks posed by air pollutants in far lesser concentrations than previously understood, the World Health Organisation (WHO) revised the permissible limits for five major pollutants — particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) sulfur dioxide (SO2) and carbon monoxide (CO) in its latest guidelines published on September 22.

The guidelines were published in a virtual event presided by WHO Director General Tedros Adhanom Ghebreyesus who pointed out that while air pollution is a threat to health in all countries, it hits people in low and middle-income countries the hardest.

“WHO’s new Air Quality Guidelines are an evidence-based and practical tool for improving the quality of the air on which all life depends. I urge all countries and all those fighting to protect our environment to put them to use to reduce suffering and save lives,” the WHO chief added.

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WHO’s revised guidelines have reduced the prescribed tolerance for annual PM 2.5 average at 5 ug/m3, reducing it from 2005 limits set at 10 ug/m3. 

Also, the PM10 annual average is now set at 15 ug/m3 in comparison to the earlier acceptable limit of 20 ug/m3. NO2 levels, which are a direct result of vehicular emissions, have been revised to 10 ug/m3, in comparison to 40 ug/m3 in the earlier set of guidelines released in 2005. 

The air has suspended particulate matter (PM) of different sizes and many of these are a complex mixture of dust, pollen, soot and smoke and they are hazardous. Of this, PM 2.5 is the smaller kind, with a diameter not more than 2.5 micrometers (fine particles). PM2.5 is considered to have an adverse health impact as it can stay in the air for days or weeks, and is small enough to invade the lung airways.

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Why have acceptable limits for pollutants been reduced?

In its remarks on the revised guidelines, WHO stated that since the last 2005 global update on air pollutants, there has been a marked increase of evidence that shows how air pollution affects different aspects of health. 

“For that reason, and after a systematic review of the accumulated evidence, WHO has adjusted almost all the AQGs (Air Quality Guidelines) levels downwards, warning that exceeding the new air quality guideline levels is associated with significant risks to health,” WHO stated in its report.

All of India’s 1.3 billion people live in areas where the annual average particulate pollution level exceeds the WHO guideline.

It also informed that every year, exposure to air pollution is estimated to cause seven million premature deaths and result in the loss of millions more healthy years of life. 

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WHO claimed that almost 80 per cent of global deaths related to PM 2.5 could be avoided if the current air pollution levels were reduced to those proposed in the updated guideline.

Implications for India

According to Global Strategic Communications Council, the national capital’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, Chennai 5.4, Hyderabad seven fold and Ahmedabad exceeded 9.8 fold. 

Also, according to a report published by the Energy Policy Institute at the University of Chicago (EPIC) on Air Quality Life Index (AQLI) — a pollution index that translates particulate air pollution into its impact on life expectancy, in 2019, India’s average particulate matter concentration was 70.3 µg/m³ — the highest in the world and seven times the WHO’s earlier guideline of 10 µg/m³. 

WHO’s revised guidelines have reduced the prescribed tolerance for annual PM 2.5 average at 5 ug/m3, reducing it from 2005 limits set at 10 ug/m3.

It also mentioned that nearly 40 per cent of India’s population is exposed to pollution levels not seen in any other country across the world. 

The report stated that over 510 million residents of northern India, including those in Delhi and Kolkata, are expected to lose 8.5 years of life expectancy on an average, if these pollution levels persist.

“All of India’s 1.3 billion people live in areas where the annual average particulate pollution level exceeds the WHO guideline. Air pollution shortens average Indian life expectancy by 5.9 years, relative to what it would be if the WHO guideline was met,” stated AQLI report.

“Air pollution is a severe health crisis and WHO’s revised air quality guidelines bring back the focus to the issue. There are no two ways about the need for revising India’s air quality standards to make them more stringent,” SN Tripathi, Professor, Indian Institute of Technology Kanpur & Steering Committee Member, National Clean Air Programme was quoted.

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“Even at the current relaxed standard of 40 ug/m3 for annual PM2.5 averages in India vs WHO’s 2005 annual limit of 10 ug/m3, most Indian cities failed to meet even those levels,” he added.

The professor also stated that India needs to strengthen its health data and revise the National Clean Air Programme accordingly. 

Also, Arun Sharma, Director, National Institute for Implementation Research of Non-Communicable Diseases, Indian Council of Medical Research stated that it is a huge challenge for countries like India to meet the revised guidelines of WHO. 

“WHO by reducing the PM2.5 and 10 exposure levels under the new AQG has reemphasised the need for putting in more efforts to control particulate matter concentration in air. But for countries like India, it is a huge challenge 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. 

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