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 12 Sep 2024: Pakistan 41.5 µg/m³, Chile 27.9 µg/m³ and Peru 27.8 µg/m³.
- 1Pakistan4 cities41.5
- 2Chile45 cities27.9
- 3Peru15 cities27.8
- 4China3 cities22.3
- 5India5 cities20.7
- 6Hungary4 cities17.1
- 7Thailand16 cities14.9
- 8Serbia10 cities14.4
- 9Singapore5 cities13.3
- 10Poland73 cities13.0
- 11South Korea140 cities12.4
- 12Taiwan43 cities10.6
- 13Japan549 cities10.4
- 14Hong Kong13 cities9.9
- 15Norway17 cities9.9
- 16United Kingdom64 cities7.8
- 17The Netherlands20 cities7.2
- 18Australia35 cities6.6
- 19United States798 cities6.5
- 20Bulgaria5 cities6.0
+ 3 more countries, 6.0 µg/m³ and below
Not counted on this day, too few cities measured: Mexico since 12 Sep 2024, Belgium since 17 Aug 2024, Switzerland 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.