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 Mar 2023: Pakistan 40.0 µg/m³, Chile 24.4 µg/m³ and Mexico 23.0 µg/m³.
- 1Pakistan4 cities40.0
- 2Chile38 cities24.4
- 3Mexico41 cities23.0
- 4Romania6 cities18.6
- 5Kosovo4 cities18.0
- 6Bulgaria5 cities17.5
- 7Brazil13 cities16.8
- 8Italy21 cities16.8
- 9Poland63 cities16.7
- 10Slovakia24 cities16.6
- 11South Africa5 cities16.1
- 12Greece7 cities15.6
- 13Czechia24 cities14.3
- 14Hungary7 cities10.4
- 15Austria24 cities9.1
- 16Spain83 cities7.4
- 17United States633 cities7.3
- 18France108 cities6.5
- 19Ireland4 cities6.5
- 20Belgium37 cities6.3
+ 10 more countries, 6.0 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.