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 29 Sep 2024: Pakistan 67.5 µg/m³, China 25.1 µg/m³ and Chile 24.0 µg/m³.
- 1Pakistan3 cities67.5
- 2China3 cities25.1
- 3Chile44 cities24.0
- 4Peru16 cities21.8
- 5India5 cities20.5
- 6Thailand16 cities, was 6616.9
- 7Hungary4 cities16.0
- 8Serbia24 cities13.0
- 9Hong Kong13 cities12.9
- 10Singapore5 cities12.2
- 11Poland71 cities10.1
- 12Bulgaria5 cities8.0
- 13Taiwan43 cities8.0
- 14South Korea141 cities7.2
- 15Japan554 cities6.8
- 16Australia35 cities6.2
- 17New Zealand6 cities5.9
- 18Norway18 cities5.7
- 19United Kingdom60 cities5.6
- 20United States788 cities5.0
+ 3 more countries, 4.9 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 21 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.