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 20 Apr 2023: India 63.0 µg/m³, Thailand 46.7 µg/m³ and China 43.4 µg/m³.
- 1India3 cities63.0
- 2Thailand11 cities46.7
- 3China3 cities43.4
- 4Pakistan4 cities36.9
- 5Chile43 cities25.6
- 6Mexico45 cities21.7
- 7Peru4 cities21.1
- 8Singapore5 cities15.2
- 9Belgium36 cities12.6
- 10Czechia29 cities11.4
- 11United Kingdom49 cities10.2
- 12Greece8 cities10.1
- 13The Netherlands31 cities10.1
- 14Germany185 cities9.9
- 15Romania7 cities9.7
- 16Ireland4 cities9.6
- 17Slovakia25 cities9.2
- 18Hungary8 cities9.1
- 19Bulgaria7 cities8.9
- 20Luxembourg3 cities8.7
+ 11 more countries, 8.2 µg/m³ and below
- 26United States679 cities7.2
Not counted on this day, too few cities measured: Australia since 15 Apr 2023, Hong Kong since 15 Apr 2023, Norway since 15 Apr 2023 and 12 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.