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Mapped: Cities With the Worst Winter Air Pollution
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Every November, Delhi, India faces the world’s worst winter air pollution, forcing school closures, halting construction, and restricting traffic into the city.
This annual spike is precipitated by farmers in northern India burning crop residue. Colder temperatures trap the smoke in the air and winds send this deadly smog across the plains, and into the capital.
Delhi’s air quality index (AQI) currently stands at 300—58x worse than the WHO’s clean air guidelines.
For reference, IQAir’s AQI categorizes pollution levels based on 6 air pollutants, including PM2.5 and carbon monoxide, into:
- Moderate: 51-100
- Unhealthy for sensitive groups: 101-150
- Unhealthy: 151-200
- Very unhealthy: 201-300
- Hazardous: 301+
But how does Delhi’s hazardous air compare globally? Using IQAir’s data from November 18, 2024, we map the most polluted cities.
Ranked: Cities by Worst Air Quality in November
Delhi’s air quality is also impacted by significant auto emissions. The city has over two million privately registered vehicles, and hundreds of thousands of taxis to serve its 30 million residents.
| Rank | City | Country | Air Quality Index Score |
|---|---|---|---|
| 1 | Delhi | 🇮🇳 India | 429 |
| 2 | Lahore | 🇵🇰 Pakistan | 395 |
| 3 | Cairo | 🇪🇬 Egypt | 285 |
| 4 | Karachi | 🇵🇰 Pakistan | 200 |
| 5 | Baghdad | 🇮🇶 Iraq | 185 |
| 6 | Kolkata | 🇮🇳 India | 181 |
| 7 | Sarajevo | 🇧🇦 Bosnia & Herzegovina |
174 |
| 8 | Ulaanbaatar | 🇲🇳 Mongolia | 166 |
| 9 | Skopje | 🇲🇰 North Macedonia | 162 |
| 10 | Dhaka | 🇧🇩 Bangladesh | 154 |
Meanwhile, ranked second, neighboring Lahore (AQI: 395), mirrors Delhi’s problems: seasonal crop stubble burning, industrial emissions, and vehicle exhausts, all trapped by colder air.
And across the Arabian peninsula, Cairo, Egypt (ranked third, AQI: 285) is also struggling with much of the same: transportation emissions and industrial pollutants, but made worse from dust blown in from the desert.
Geography also plays a role, as in the case of Sarajevo, in Bosnia and Herzegovina, (ranked seventh, AQI: 174). Pollutants generated in the city stay trapped within the deep valley, surrounded by high mountains.
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India and Pakistan are also in the ranks for Countries With the Worst Air Pollution. But another South Asian country ranks first.