Important Facts For Prelims
World Air Quality Report 2024
- 15 Mar 2025
- 4 min read
Why in News?
The World Air Quality Report 2024, released by Swiss company IQAir, ranked India as the 5th most polluted country globally.
What are the Key Findings of the World Air Quality Report?
- India: India is the 5th most polluted country in 2024, improving slightly from 3rd place in 2023.
- Polluted Cities: Delhi remains the most polluted capital globally with a Particulate matter (PM) 2.5 concentration of 91.6 µg/m³ (micrograms per cubic metre).
- 6 of the world's 10 most polluted cities and 13 of the top 20 are in India, with Byrnihat (Assam-Meghalaya border) topping the list at a PM2.5 concentration of 128.2 µg/m³.
- Other polluted cities include Mullanpur (Punjab), Gurugram, Faridabad, Bhiwadi, and Noida.
- 6 of the world's 10 most polluted cities and 13 of the top 20 are in India, with Byrnihat (Assam-Meghalaya border) topping the list at a PM2.5 concentration of 128.2 µg/m³.
- PM2.5 Reduction: India saw a 7% decrease in PM2.5 levels, averaging 50.6 µg/m³ in 2024, down from 54.4 µg/m³ in 2023.
- However, this is still 10 times higher than the World Health Organization (WHO's) recommended safe limit of 5 µg/m³. 35% of Indian cities reported PM2.5 levels exceeding this limit.
- Pollution Sources: Major contributors include vehicle emissions, industrial pollution, and the burning of biomass.
- Northern India faced extreme pollution levels with crop stubble-burning contributing to 60% of PM2.5 levels.
- Polluted Cities: Delhi remains the most polluted capital globally with a Particulate matter (PM) 2.5 concentration of 91.6 µg/m³ (micrograms per cubic metre).
- Global: The most polluted countries by annual average PM2.5 levels are Chad (91.8 µg/m³), Bangladesh (78 µg/m³), Pakistan (73.7 µg/m³), and Congo (58.2 µg/m³).
- The report highlights that most of the global population is breathing polluted air, with only 12 countries, regions, or territories reporting PM2.5 concentrations below the WHO’s recommended limit.
Air Pollution
- Air pollution is the contamination of air by chemical, physical, or biological agents that alter its natural composition.
- Major sources include combustion, vehicles, industries, and fires. Pollutants like PM, CO, O₃, NO₂, and SO₂ cause respiratory diseases and high mortality.
- WHO reports that 99% of the global population breathes polluted air, with low- and middle-income countries most affected.
- Prolonged PM2.5 exposure cuts life expectancy by 5.2 years in India, linked to 1.5 million annual deaths between 2009–2019, as per the Lancet Planetary Health Study.
- WHO Air Quality Guidelines (AQG) aim to help governments reduce air pollution and improve public health.
UPSC Civil Services Examination, Previous Year Questions (PYQs)
Prelims
In the cities of our country, which among the following atmospheric gases are normally considered in calculating the value of the Air Quality Index? (2016)
- Carbon dioxide
- Carbon monoxide
- Nitrogen dioxide
- Sulphur dioxide
- Methane
Select the correct answer using the code given below:
(a) 1, 2 and 3 only
(b) 2, 3 and 4 only
(c) 1, 4 and 5 only
(d) 1, 2, 3, 4 and 5
Ans: (b)
Mains
Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve revised standards? (2021)
