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 Jun 2024: Chile 37.6 µg/m³, India 24.7 µg/m³ and Peru 22.6 µg/m³.
- 1Chile44 cities37.6
- 2India4 cities24.7
- 3Peru12 cities22.6
- 4China3 cities22.1
- 5Mexico5 cities18.1
- 6New Zealand5 cities15.6
- 7Brazil30 cities15.5
- 8South Korea141 cities15.3
- 9Serbia24 cities12.1
- 10North Macedonia8 cities11.5
- 11Thailand70 cities11.5
- 12Greece6 cities11.3
- 13Malta5 cities11.3
- 14Singapore6 cities10.8
- 15Poland72 cities9.7
- 16Slovakia40 cities9.5
- 17Hungary10 cities9.1
- 18Italy5 cities, was 398.8
- 19Latvia4 cities8.8
- 20Taiwan43 cities8.7
+ 22 more countries, the next at 8.3 µg/m³
- 30United States807 cities6.8
Not counted on this day, too few cities measured: Switzerland since 13 Jun 2024, Czechia since 11 Jun 2024, Pakistan since 9 Jun 2024 and 5 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.