IQAir World Air Quality Report 2024: Byrnihat most polluted city, India fifth most polluted country, Delhi most polluted capital
The 2024 World Air Quality Report by Swiss firm IQAir, released on 11 March 2025, named Byrnihat on the Assam–Meghalaya border the world's most polluted metropolitan area and ranked India the fifth most polluted country.
Summary
Swiss air-quality technology company IQAir released its seventh annual World Air Quality Report, covering 2024, on 11 March 2025. Byrnihat, an industrial town in Meghalaya on the Assam border, was the world's most polluted metropolitan area with an annual average PM2.5 concentration of 128.2 µg/m³, and six of the world's ten most polluted cities were in India. India ranked fifth among the most polluted countries at 50.6 µg/m³ — more than ten times the WHO annual guideline of 5 µg/m³ — improving from third in 2023 after a 7% fall in PM2.5. Chad was the most polluted country (91.8 µg/m³), followed by Bangladesh, Pakistan and the Democratic Republic of the Congo. New Delhi remained the most polluted capital, at about 91.6 µg/m³. Only seven countries met the WHO guideline, and only 17% of cities worldwide did.
Key facts
- Released
- 11 March 2025 by IQAir (Switzerland); 7th edition
- Most polluted city
- Byrnihat, 128.2 µg/m³ PM2.5
- Most polluted countries
- 1 Chad, 2 Bangladesh, 3 Pakistan, 4 DR Congo, 5 India
- India
- 50.6 µg/m³; 5th (3rd in 2023)
- Most polluted capital
- New Delhi
- WHO guideline
- 5 µg/m³ annual PM2.5
Practice MCQs 4 questions
Which town was named the world's most polluted metropolitan area in IQAir's World Air Quality Report 2024?
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Correct answer: B — Byrnihat
Byrnihat, on the Assam–Meghalaya border, topped the list with an annual average PM2.5 of 128.2 µg/m³.
What was India's rank among the most polluted countries in IQAir's World Air Quality Report 2024?
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Correct answer: D — Fifth
India ranked fifth at 50.6 µg/m³, improving from third in 2023.
Which country was ranked the most polluted in IQAir's World Air Quality Report 2024?
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Correct answer: A — Chad
Chad topped the list at 91.8 µg/m³, followed by Bangladesh, Pakistan, the DR Congo and India.
Consider the following statements about IQAir's World Air Quality Report 2024: 1. India's annual average PM2.5 concentration was more than ten times the WHO annual guideline of 5 µg/m³. 2. New Delhi was the most polluted capital city. Which of the above is/are correct?
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Correct answer: C — Both 1 and 2
Both are correct: India averaged 50.6 µg/m³ against the WHO guideline of 5 µg/m³, and New Delhi remained the world's most polluted capital.