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 23 May 2024: Chile 46.8 µg/m³, India 39.7 µg/m³ and Pakistan 35.1 µg/m³.
- 1Chile44 cities46.8
- 2India3 cities39.7
- 3Pakistan4 cities35.1
- 4Malta5 cities27.5
- 5Mexico10 cities24.5
- 6China3 cities22.6
- 7Laos3 cities20.5
- 8Peru11 cities19.2
- 9Greece9 cities17.6
- 10South Korea141 cities16.9
- 11Taiwan43 cities16.6
- 12Belgium44 cities15.3
- 13Thailand76 cities14.9
- 14North Macedonia9 cities13.1
- 15New Zealand5 cities13.1
- 16Hong Kong4 cities12.1
- 17The Netherlands36 cities11.5
- 18Lithuania3 cities11.0
- 19Serbia24 cities11.0
- 20Japan564 cities10.7
+ 27 more countries, 10.5 µg/m³ and below
- 38United States788 cities6.6
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 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.