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 1 Oct 2024: Pakistan 59.5 µg/m³, China 26.8 µg/m³ and Chile 22.9 µg/m³.
- 1Pakistan3 cities59.5
- 2China3 cities26.8
- 3Chile45 cities22.9
- 4Peru16 cities21.8
- 5India5 cities20.5
- 6Thailand15 cities, was 6616.6
- 7Hong Kong13 cities15.4
- 8Hungary4 cities11.8
- 9Singapore5 cities11.5
- 10Serbia24 cities11.3
- 11Taiwan43 cities9.4
- 12Japan555 cities8.1
- 13South Korea141 cities7.9
- 14Poland71 cities7.6
- 15New Zealand6 cities7.4
- 16Bulgaria5 cities6.0
- 17Australia34 cities5.2
- 18United States788 cities5.2
- 19Canada112 cities4.3
- 20The Netherlands21 cities3.9
+ 3 more countries, 3.8 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 19 Sep 2024, Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024 and 20 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.