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 Mar 2023: Pakistan 40.0 µg/m³, Chile 24.8 µg/m³ and Mexico 23.5 µg/m³.
- 1Pakistan4 cities40.0
- 2Chile42 cities24.8
- 3Mexico47 cities23.5
- 4Bulgaria5 cities16.5
- 5South Africa8 cities16.5
- 6Romania7 cities16.4
- 7Kosovo4 cities15.9
- 8Greece7 cities15.5
- 9Brazil13 cities15.1
- 10Italy22 cities14.4
- 11Poland65 cities14.0
- 12Slovakia25 cities13.9
- 13Czechia25 cities12.4
- 14Hungary7 cities9.5
- 15Austria24 cities7.6
- 16Spain85 cities7.6
- 17United States659 cities7.3
- 18Ireland4 cities6.6
- 19France107 cities6.2
- 20Belgium37 cities5.8
+ 10 more countries, 5.7 µg/m³ and below
Not counted on this day, too few cities measured: Luxembourg since 26 Mar 2023, Bosnia and Herzegovina since 22 Mar 2023, Latvia since 22 Mar 2023 and 12 more countries. Days missing from the source archive fall in this window, so fewer countries are counted.
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.