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 13 Apr 2024: Laos 62.3 µg/m³, China 46.5 µg/m³ and Pakistan 39.6 µg/m³.
- 1Laos3 cities62.3
- 2China4 cities46.5
- 3Pakistan4 cities39.6
- 4Thailand78 cities39.6
- 5India5 cities39.5
- 6Chile45 cities24.2
- 7Peru4 cities23.3
- 8South Korea139 cities21.9
- 9Taiwan42 cities21.2
- 10Hong Kong8 cities19.0
- 11Mexico12 cities18.3
- 12Serbia24 cities13.8
- 13North Macedonia9 cities12.6
- 14Romania7 cities12.3
- 15Slovakia39 cities12.0
- 16Italy35 cities, was 3911.9
- 17Poland78 cities11.9
- 18Malta5 cities11.5
- 19Czechia38 cities11.4
- 20Bosnia and Herzegovina5 cities11.1
+ 26 more countries, 11.0 µg/m³ and below
- 38United States788 cities5.4
Not counted on this day, too few cities measured: Belgium since 13 Apr 2024, Montenegro since 22 Mar 2024, Austria since 13 Mar 2024 and 4 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.