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 29 Apr 2023: India 40.6 µg/m³, Chile 29.7 µg/m³ and Pakistan 27.4 µg/m³.
- 1India3 cities40.6
- 2Chile41 cities29.7
- 3Pakistan3 cities27.4
- 4Mexico27 cities23.4
- 5Poland58 cities12.5
- 6Slovakia24 cities12.2
- 7Greece9 cities12.1
- 8Hungary8 cities12.1
- 9Czechia24 cities11.4
- 10Belgium37 cities10.5
- 11United Kingdom3 cities10.1
- 12Romania7 cities9.2
- 13Bulgaria7 cities8.9
- 14Ireland4 cities8.8
- 15Austria22 cities8.7
- 16Italy20 cities8.5
- 17Germany182 cities7.7
- 18Spain83 cities7.3
- 19United States647 cities6.9
- 20The Netherlands15 cities6.6
+ 8 more countries, 6.0 µg/m³ and below
Not counted on this day, too few cities measured: China since 25 Apr 2023, Luxembourg since 25 Apr 2023, Singapore since 25 Apr 2023 and 15 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.