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 26 Jun 2025: Chile 44.4 µg/m³, Pakistan 41.4 µg/m³ and Peru 29.6 µg/m³.
- 1Chile45 cities44.4
- 2Pakistan9 cities41.4
- 3Peru5 cities29.6
- 4India189 cities23.2
- 5New Zealand10 cities16.4
- 6Italy20 cities14.5
- 7Bosnia and Herzegovina5 cities13.3
- 8Malta4 cities13.3
- 9Slovenia12 cities13.3
- 10Martinique3 cities12.8
- 11Slovakia38 cities12.1
- 12South Korea140 cities11.9
- 13Serbia38 cities11.9
- 14Spain88 cities, was 9911.6
- 15Thailand75 cities10.2
- 16Greece8 cities9.9
- 17Hungary11 cities, was 49.7
- 18Japan566 cities8.7
- 19United States838 cities8.6
- 20Mexico36 cities8.5
+ 21 more countries, 8.4 µg/m³ and below
Not counted on this day, too few cities measured: Lithuania since 25 Jun 2025, Luxembourg since 9 Jun 2025, Portugal since 9 Jun 2025 and 3 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.