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 12 Jun 2024: Chile 26.4 µg/m³, India 25.8 µg/m³ and Mexico 22.9 µg/m³.
- 1Chile45 cities26.4
- 2India4 cities25.8
- 3Mexico13 cities22.9
- 4China4 cities21.2
- 5Peru13 cities21.2
- 6New Zealand5 cities18.5
- 7South Korea140 cities17.8
- 8Serbia24 cities12.9
- 9Greece5 cities12.4
- 10Italy15 cities11.7
- 11Thailand71 cities11.4
- 12Singapore5 cities11.1
- 13North Macedonia8 cities11.0
- 14Poland70 cities9.7
- 15Hungary11 cities9.5
- 16Malta5 cities9.4
- 17Slovenia12 cities9.2
- 18Romania8 cities9.1
- 19Slovakia40 cities9.0
- 20Bosnia and Herzegovina4 cities8.8
+ 21 more countries, 8.3 µg/m³ and below
- 34United States798 cities5.4
Not counted on this day, too few cities measured: Switzerland since 6 Jun 2024, Iceland since 6 Jun 2024, Czechia since 3 Jun 2024 and 7 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.