From UPSC perspective, the following things are important :
Prelims level : PM 2.5
Mains level : World Air Quality Report, 2019
The 2019 World Air Quality Report was recently released
World Air Quality Report
- The World Air Quality Report is released by the pollution tracker IQAir and Greenpeace.
- The report focuses on PM2.5 as a representative measure of air pollution.
Highlights of the report
- India accounts for two-thirds of the world’s most polluted cities — 21 of the most polluted 30 cities; 14 of the highest 20; and 6 of the highest 10 — in the report.
- Among countries, when population is taken into account, average PM2.5 pollution is highest in Bangladesh, followed by Pakistan, while India is at number 5.
- China is at number 11 in the list of countries affected by population, with population factored in. Chinese cities achieved a 9% average decrease in PM2.5 levels in 2019.
- While cities in India, on average, exceed the WHO target for annual PM2.5 exposure by 500%, national air pollution decreased by 20% from 2018 to 2019, with 98% of cities experiencing improvements.
- It said 90% of the global population breathing unsafe air.
Top polluted Indian Cities
- PM 2.5 refers to particulate matter (ambient airborne particles) which measure up to 2.5 microns in size and has a range of chemical makeups and sources.
- It is widely regarded as the pollutant with the most health impact of all commonly measured air pollutants.
- Due to its small size PM2.5 is able to penetrate deep into the human respiratory system and from there to the entire body, causing a wide range of short- and long-term health effects.
- Particulate matter is also the pollutant group which affects the most people globally. It can come from a range of natural as well as man-made sources.
- Common sources of PM include combustion (from vehicle engines, industry, wood and coal burning), as well as through other pollutants reacting in the atmosphere.