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 24 Apr 2023: India 51.6 µg/m³, Thailand 42.5 µg/m³ and China 33.5 µg/m³.
- 1India3 cities51.6
- 2Thailand10 cities42.5
- 3China3 cities33.5
- 4Pakistan4 cities28.6
- 5Chile43 cities25.5
- 6Mexico38 cities23.8
- 7Poland67 cities15.1
- 8Ireland4 cities13.8
- 9Czechia28 cities13.6
- 10Slovakia24 cities13.4
- 11Belgium37 cities13.2
- 12Hungary8 cities12.1
- 13Greece7 cities11.7
- 14United Kingdom38 cities11.4
- 15Singapore5 cities10.9
- 16Romania7 cities10.7
- 17Bulgaria7 cities10.6
- 18Austria23 cities9.9
- 19The Netherlands28 cities9.1
- 20Germany185 cities9.0
+ 12 more countries, 9.0 µg/m³ and below
- 26United States618 cities6.8
Not counted on this day, too few cities measured: Serbia since 24 Apr 2023, Peru since 22 Apr 2023, Australia since 15 Apr 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.