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 26 Jul 2024: Chile 53.1 µg/m³, Peru 24.0 µg/m³ and China 21.1 µg/m³.
- 1Chile44 cities53.1
- 2Peru14 cities24.0
- 3China3 cities21.1
- 4New Zealand5 cities16.6
- 5India4 cities16.3
- 6Malta5 cities14.1
- 7Singapore5 cities14.0
- 8Serbia24 cities13.4
- 9North Macedonia9 cities13.2
- 10Slovakia41 cities12.8
- 11Italy10 cities12.5
- 12Thailand15 cities, was 8012.4
- 13Greece6 cities11.5
- 14Hungary11 cities10.7
- 15Romania9 cities9.9
- 16Slovenia12 cities9.8
- 17South Korea141 cities9.6
- 18Czechia36 cities9.4
- 19Japan559 cities9.4
- 20Poland76 cities9.3
+ 24 more countries, 9.2 µg/m³ and below
- 23United States796 cities7.9
Not counted on this day, too few cities measured: Spain since 24 Jul 2024, Pakistan since 22 Jul 2024, Bosnia and Herzegovina since 20 Jul 2024 and 2 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.