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 30 days to 14 Jun 2025: Chile 51.0 µg/m³, Peru 33.6 µg/m³ and India 30.0 µg/m³.
- 1Chile47 cities51.0
- 2Peru4 cities33.6
- 3India194 cities30.0
- 4Mexico42 cities18.4
- 5South Korea139 cities16.6
- 6Thailand78 cities12.9
- 7New Zealand6 cities12.3
- 8Serbia38 cities11.5
- 9Hong Kong13 cities10.5
- 10France7 cities, was 9710.2
- 11Japan564 cities10.2
- 12Canada112 cities9.9
- 13Italy10 cities9.8
- 14Switzerland10 cities9.3
- 15Taiwan45 cities8.9
- 16Latvia4 cities8.7
- 17Spain94 cities, was 1148.6
- 18Poland73 cities8.5
- 19Slovakia41 cities8.4
- 20Romania10 cities8.1
+ 15 more countries, 8.0 µg/m³ and below
- 22United States834 cities8.0
Not counted on this day, too few cities measured: Malta since 14 Jun 2025, Kosovo since 13 Jun 2025, Portugal since 12 Jun 2025 and 7 more countries.
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.