SmogRank / History / Country race
Countries, worst air first, day by day
Each country's typical measured city over the 30 days to every day since January 2023, worst first. Press Play to watch the order change, or drag the slider to any day.
The worst countries for PM2.5 over the 7 days to 4 May 2026: Pakistan 33.5 µg/m³, Chile 33.2 µg/m³ and Peru 32.8 µg/m³.
- 1Pakistan15 cities33.5
- 2Chile46 cities33.2
- 3Peru6 cities32.8
- 4India205 cities29.5
- 5Laos3 cities28.8
- 6Thailand84 cities21.1
- 7Malawi5 cities18.6
- 8Mexico46 cities18.6
- 9Kazakhstan4 cities16.8
- 10South Korea139 cities15.4
- 11Taiwan44 cities13.8
- 12Lebanon3 cities13.7
- 13Serbia8 cities12.3
- 14Hong Kong13 cities11.3
- 15Senegal3 cities10.8
- 16New Zealand6 cities10.2
- 17United Kingdom5 cities10.0
- 18North Macedonia14 cities9.9
- 19Malta5 cities9.8
- 20Romania26 cities9.6
+ 31 more countries, 9.4 µg/m³ and below
- 43United States847 cities5.1
Not counted on this day, too few cities measured: Poland since 16 Apr 2026, Ghana since 8 Apr 2026, Philippines since 6 Apr 2026 and Kyrgyzstan since 25 Mar 2026.
Countries counted each day
A country's number is its typical measured city: the median of its cities' means over the 30 days (a city needs 21 of them measured; 5 of 7 on the 7-day race), shown only with 3 such cities. A country whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air; "was" beside a city count marks a month after many cities joined or left. Some large countries are thin or missing because their monitors' licences don't allow reuse. How we rank.
Not covered: the government monitoring networks of China and Turkey, which publish only on their own websites; we are building the readers for them. Most cities there are missing from this board, not clean. Why.