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 25 Mar 2023: Pakistan 40.9 µg/m³, Chile 23.6 µg/m³ and Mexico 21.4 µg/m³.
- 1Pakistan4 cities40.9
- 2Chile38 cities23.6
- 3Mexico39 cities21.4
- 4Romania6 cities21.4
- 5Poland64 cities20.3
- 6Slovakia24 cities18.6
- 7Bulgaria5 cities18.0
- 8Italy23 cities17.6
- 9Kosovo6 cities17.5
- 10South Africa6 cities17.3
- 11Czechia28 cities17.2
- 12Brazil13 cities15.5
- 13Greece7 cities15.2
- 14Hungary6 cities12.5
- 15Austria24 cities11.9
- 16Spain84 cities7.6
- 17United States606 cities7.1
- 18Germany178 cities6.7
- 19Belgium37 cities6.6
- 20France109 cities6.6
+ 11 more countries, 6.5 µg/m³ and below
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 22 Mar 2023, Latvia since 22 Mar 2023, North Macedonia since 22 Mar 2023 and 11 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.