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 27 May 2024: Chile 48.0 µg/m³, Pakistan 39.4 µg/m³ and Mexico 27.1 µg/m³.
- 1Chile44 cities48.0
- 2Pakistan4 cities39.4
- 3Mexico11 cities27.1
- 4India3 cities22.8
- 5Peru12 cities22.7
- 6China3 cities19.2
- 7South Korea141 cities17.1
- 8New Zealand5 cities15.4
- 9Laos3 cities12.4
- 10Taiwan43 cities12.0
- 11Greece8 cities11.7
- 12Australia15 cities11.6
- 13Serbia24 cities11.2
- 14Poland74 cities11.0
- 15Lithuania4 cities10.8
- 16Malta5 cities10.7
- 17Thailand77 cities10.7
- 18Japan562 cities10.5
- 19Latvia4 cities10.2
- 20Hong Kong7 cities, was 119.9
+ 28 more countries, 9.3 µg/m³ and below
- 36United States776 cities6.6
Not counted on this day, too few cities measured: Puerto Rico since 23 May 2024, Austria since 10 May 2024 and Bosnia and Herzegovina since 26 Apr 2024.
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.