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 24 Jul 2024: Chile 53.7 µg/m³, China 30.5 µg/m³ and Peru 22.1 µg/m³.
- 1Chile44 cities53.7
- 2China4 cities30.5
- 3Peru15 cities22.1
- 4New Zealand5 cities17.0
- 5Brazil33 cities16.4
- 6India4 cities15.9
- 7Malta5 cities14.0
- 8Serbia24 cities13.8
- 9North Macedonia9 cities13.5
- 10Singapore6 cities13.4
- 11Slovakia41 cities13.0
- 12Italy10 cities12.4
- 13Thailand18 cities, was 8012.1
- 14Greece6 cities11.5
- 15Hungary10 cities10.7
- 16Slovenia12 cities10.1
- 17South Korea141 cities10.0
- 18Romania9 cities9.9
- 19Japan559 cities9.7
- 20Czechia32 cities9.6
+ 25 more countries, the next at 9.4 µg/m³
- 25United States799 cities7.8
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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.