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 25 May 2024: Chile 45.4 µg/m³, Pakistan 38.5 µg/m³ and Mexico 26.7 µg/m³.
- 1Chile44 cities45.4
- 2Pakistan4 cities38.5
- 3Mexico11 cities26.7
- 4India3 cities22.6
- 5Peru12 cities20.9
- 6Malta5 cities20.5
- 7China3 cities18.5
- 8South Korea141 cities18.1
- 9Laos3 cities16.2
- 10Greece8 cities14.9
- 11New Zealand5 cities14.1
- 12Taiwan43 cities14.1
- 13Brazil32 cities13.0
- 14Belgium44 cities12.8
- 15Thailand76 cities12.0
- 16North Macedonia9 cities11.9
- 17Poland76 cities11.1
- 18Serbia24 cities11.0
- 19Japan560 cities10.8
- 20Latvia4 cities10.6
+ 28 more countries, the next at 10.3 µg/m³
- 38United States794 cities6.7
Not counted on this day, too few cities measured: Puerto Rico since 23 May 2024, Luxembourg since 19 May 2024, Austria since 10 May 2024 and Bosnia and Herzegovina since 26 Apr 2024.
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.