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 30 Apr 2023: India 36.5 µg/m³, Pakistan 31.1 µg/m³ and Chile 29.0 µg/m³.
- 1India3 cities36.5
- 2Pakistan3 cities31.1
- 3Chile41 cities29.0
- 4China3 cities28.6
- 5Thailand9 cities25.3
- 6Mexico28 cities22.6
- 7Poland58 cities12.1
- 8Greece9 cities12.0
- 9United Kingdom3 cities11.6
- 10Belgium37 cities11.5
- 11Slovakia24 cities11.4
- 12Czechia25 cities11.3
- 13Hungary8 cities10.7
- 14Singapore5 cities9.0
- 15Romania7 cities8.8
- 16Austria23 cities8.7
- 17Bulgaria7 cities8.4
- 18Italy20 cities8.2
- 19Malta3 cities7.9
- 20Germany182 cities7.7
+ 12 more countries, 7.6 µg/m³ and below
- 23United States669 cities6.8
Not counted on this day, too few cities measured: Luxembourg since 25 Apr 2023, Serbia since 24 Apr 2023, Peru since 22 Apr 2023 and 12 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.