In News: According to a report titled Air Quality and Health in Cities, published by the United States-based Health Effects Institute, Delhi and Kolkata are the top two most polluted cities in terms of exposure to harmful fine particulate matter (PM2.5).
- The report examines pollution and global health implications in over 7,000 cities worldwide, focussing on two of the most dangerous pollutants – fine particulate matter (PM2.5) and nitrogen dioxide (NO2).
Overall findings of the Air Quality and Health in Cities report:
- According to the report, while exposures to 5 and NO2 pollution tend to be higher in cities located in low and middle-income countries,
- The report found most global cities far exceed World Health Organisation’s (WHO) air pollution guidelines, posing serious health risk.
- In 2019, 86% of the cities analysed exceeded the WHO’s 10 µg/m3 (microgram per cubic metre) guideline for NO2, impacting about 2.6 billion people.
- 41 of the 50 cities with the highest increase in PM2.5 are in India, with 9 in Indonesia.
- On the other hand, all 20 cities with the highest reduction in PM2.5 pollution from 2010 to 2019 are in China.
India specific findings:
- Delhi and Kolkata were ranked first and second in the list of top 10 most polluted cities when PM2.5 levels were compared.
- In terms of impact, Delhi and Kolkata ranked sixth and eighth for PM2.5 related disease burden, reporting 106 deaths and 99 deaths per lakh of population, respectively due to exposure to 5 in 2019.
- However, no Indian city appeared in the list of top 20 polluted cities when N02 levels were compared (Shanghai at the top with an average annual exposure of 41 µg/m3).
Short-lived climate pollutants: Short-lived climate pollutants (SLCPs) are powerful climate forcers that remain in the atmosphere for a much shorter period than longer-lived climate pollutants, such as carbon dioxide (CO2). They include methane, PM 2.5, NO2, fluorinated gases including hydrofluorocarbons (HFCs), and black carbon.
Source: The Hindu
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