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 30 days to 19 May 2023: India 43.0 µg/m³, Chile 36.1 µg/m³ and Pakistan 34.4 µg/m³.
- 1India3 cities43.0
- 2Chile43 cities36.1
- 3Pakistan4 cities34.4
- 4Thailand11 cities23.4
- 5Mexico13 cities22.9
- 6Serbia3 cities14.4
- 7Greece7 cities12.5
- 8Czechia29 cities12.3
- 9Poland42 cities11.9
- 10Belgium37 cities11.8
- 11Malta3 cities10.8
- 12Slovakia24 cities10.2
- 13Hungary7 cities9.8
- 14United Kingdom5 cities9.5
- 15Bulgaria6 cities9.4
- 16Romania7 cities9.2
- 17Luxembourg3 cities9.1
- 18Austria24 cities8.8
- 19Germany185 cities8.5
- 20The Netherlands14 cities8.4
+ 11 more countries, 8.3 µg/m³ and below
- 22United States693 cities7.4
Not counted on this day, too few cities measured: Norway since 19 May 2023, Singapore since 16 May 2023, China since 13 May 2023 and 10 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.