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 25 Aug 2024: Pakistan 35.6 µg/m³, Chile 34.6 µg/m³ and Peru 23.6 µg/m³.
- 1Pakistan4 cities35.6
- 2Chile43 cities34.6
- 3Peru14 cities23.6
- 4China4 cities19.3
- 5India5 cities16.3
- 6South Korea141 cities14.3
- 7Serbia12 cities12.6
- 8Thailand16 cities, was 912.6
- 9Hungary5 cities12.3
- 10Singapore5 cities11.8
- 11New Zealand5 cities11.2
- 12Poland70 cities10.5
- 13Hong Kong12 cities9.3
- 14Mexico3 cities8.2
- 15Japan554 cities7.7
- 16Taiwan43 cities7.7
- 17Bulgaria5 cities7.4
- 18United States811 cities7.3
- 19United Kingdom61 cities6.7
- 20The Netherlands20 cities6.7
+ 4 more countries, 6.4 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.