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 2 May 2024: Laos 62.2 µg/m³, India 47.2 µg/m³ and Pakistan 40.9 µg/m³.
- 1Laos3 cities62.2
- 2India4 cities47.2
- 3Pakistan3 cities40.9
- 4Thailand82 cities, was 1327.6
- 5Chile46 cities26.4
- 6China3 cities25.4
- 7Peru14 cities20.8
- 8Mexico11 cities18.7
- 9South Korea140 cities17.9
- 10Malta5 cities12.5
- 11Poland78 cities12.1
- 12Latvia4 cities11.5
- 13Taiwan43 cities11.2
- 14Serbia24 cities10.9
- 15Slovakia41 cities10.8
- 16Lithuania4 cities10.7
- 17Slovenia12 cities10.4
- 18Belgium44 cities10.3
- 19Japan565 cities9.9
- 20Hong Kong12 cities9.8
+ 27 more countries, 9.6 µg/m³ and below
- 35United States796 cities6.4
Not counted on this day, too few cities measured: Austria since 26 Apr 2024, Bosnia and Herzegovina since 26 Apr 2024, Montenegro since 22 Mar 2024 and 3 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 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.