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 5 May 2026: Chile 34.1 µg/m³, Pakistan 34.1 µg/m³ and Peru 31.9 µg/m³.
- 1Chile47 cities34.1
- 2Pakistan15 cities34.1
- 3Peru6 cities31.9
- 4India203 cities28.2
- 5Laos3 cities28.0
- 6Thailand82 cities20.4
- 7Malawi5 cities18.9
- 8Mexico48 cities18.6
- 9Kazakhstan4 cities17.0
- 10South Korea138 cities14.9
- 11Lebanon3 cities13.7
- 12Taiwan44 cities12.9
- 13Serbia8 cities12.5
- 14Hong Kong13 cities11.2
- 15New Zealand6 cities10.7
- 16Senegal3 cities10.7
- 17United Kingdom5 cities10.1
- 18Czechia3 cities9.9
- 19Brazil6 cities9.7
- 20Romania26 cities9.7
+ 31 more countries, 9.6 µg/m³ and below
- 42United States849 cities5.3
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.