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 8 May 2023: Laos 38.2 µg/m³, Chile 36.9 µg/m³ and Pakistan 33.5 µg/m³.
- 1Laos3 cities38.2
- 2Chile42 cities36.9
- 3Pakistan4 cities33.5
- 4Mexico13 cities, was 4729.5
- 5India3 cities25.4
- 6Thailand77 cities25.1
- 7China3 cities23.4
- 8South Africa11 cities16.4
- 9Serbia22 cities14.2
- 10Greece8 cities12.8
- 11Czechia29 cities11.5
- 12Belgium37 cities11.3
- 13Hong Kong12 cities10.5
- 14Slovakia25 cities10.4
- 15Austria24 cities10.2
- 16Poland65 cities10.2
- 17Hungary7 cities10.1
- 18Italy24 cities9.6
- 19Bulgaria7 cities8.9
- 20Germany183 cities8.6
+ 17 more countries, 8.4 µg/m³ and below
- 31United States698 cities5.4
Not counted on this day, too few cities measured: Luxembourg since 25 Apr 2023, Peru since 22 Apr 2023, Brazil since 7 Apr 2023 and 7 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.