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 30 days to 11 Sep 2024: Chile 35.4 µg/m³, Pakistan 34.8 µg/m³ and Peru 25.1 µg/m³.
- 1Chile44 cities35.4
- 2Pakistan4 cities34.8
- 3Peru13 cities25.1
- 4China3 cities20.1
- 5India5 cities19.1
- 6Hungary4 cities17.0
- 7Serbia10 cities15.6
- 8Singapore5 cities14.5
- 9Thailand15 cities13.3
- 10Poland71 cities12.8
- 11South Korea141 cities12.1
- 12Hong Kong13 cities11.1
- 13Taiwan43 cities10.9
- 14New Zealand5 cities9.2
- 15Japan555 cities8.0
- 16The Netherlands20 cities7.8
- 17Mexico3 cities7.7
- 18United States811 cities7.6
- 19United Kingdom63 cities7.4
- 20Bulgaria5 cities7.2
+ 4 more countries, 7.1 µg/m³ and below
Not counted on this day, too few cities measured: Belgium since 24 Aug 2024, Switzerland since 24 Aug 2024, Germany since 24 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.