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 21 May 2024: Chile 54.6 µg/m³, India 40.1 µg/m³ and Pakistan 36.3 µg/m³.
- 1Chile44 cities54.6
- 2India4 cities40.1
- 3Pakistan4 cities36.3
- 4Malta5 cities32.5
- 5China3 cities24.6
- 6Mexico10 cities22.6
- 7Laos3 cities22.2
- 8Peru12 cities19.6
- 9Thailand78 cities19.2
- 10Greece8 cities17.2
- 11Taiwan43 cities16.9
- 12Belgium44 cities13.9
- 13Hong Kong8 cities13.4
- 14South Korea141 cities13.0
- 15The Netherlands36 cities12.6
- 16New Zealand5 cities12.6
- 17North Macedonia9 cities12.1
- 18Latvia4 cities10.9
- 19Lithuania3 cities10.6
- 20Serbia24 cities10.5
+ 28 more countries, 10.0 µg/m³ and below
- 39United States798 cities6.3
Not counted on this day, too few cities measured: 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.