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 11 Sep 2024: Pakistan 38.1 µg/m³, Chile 28.0 µg/m³ and Peru 27.6 µg/m³.
- 1Pakistan4 cities38.1
- 2Chile45 cities28.0
- 3Peru15 cities27.6
- 4China3 cities22.0
- 5Hungary4 cities16.8
- 6India5 cities16.2
- 7Serbia10 cities16.1
- 8Singapore5 cities15.3
- 9Thailand16 cities14.8
- 10Poland73 cities14.1
- 11South Korea141 cities12.7
- 12Norway18 cities11.2
- 13Japan557 cities10.8
- 14Taiwan43 cities10.0
- 15Hong Kong13 cities8.9
- 16The Netherlands20 cities8.1
- 17United Kingdom64 cities7.9
- 18Bulgaria5 cities7.2
- 19Australia35 cities6.7
- 20Mexico3 cities6.5
+ 4 more countries, 6.3 µg/m³ and below
- 22United States793 cities6.3
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.