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 20 Aug 2024: Chile 42.0 µg/m³, Pakistan 30.4 µg/m³ and Peru 23.1 µg/m³.
- 1Chile42 cities42.0
- 2Pakistan4 cities30.4
- 3Peru14 cities23.1
- 4India5 cities19.2
- 5China4 cities17.2
- 6Serbia10 cities13.7
- 7Hungary5 cities12.9
- 8Thailand17 cities, was 912.6
- 9New Zealand5 cities12.5
- 10Singapore5 cities12.3
- 11Poland69 cities10.4
- 12South Korea140 cities9.9
- 13Canada116 cities9.6
- 14Hong Kong11 cities8.4
- 15United States799 cities8.4
- 16Japan561 cities8.2
- 17Mexico3 cities6.9
- 18The Netherlands20 cities6.9
- 19United Kingdom62 cities6.7
- 20Taiwan43 cities6.0
+ 4 more countries, 5.6 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024, Germany since 17 Aug 2024 and 22 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.