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 7 Jun 2023: South Africa 53.9 µg/m³, India 42.8 µg/m³ and Chile 37.7 µg/m³.
- 1South Africa5 cities53.9
- 2India5 cities42.8
- 3Chile46 cities37.7
- 4Pakistan4 cities32.9
- 5China3 cities27.5
- 6Mexico12 cities21.2
- 7Thailand9 cities, was 7716.7
- 8Martinique3 cities15.7
- 9Malta4 cities11.8
- 10Serbia3 cities, was 2111.7
- 11Greece8 cities11.5
- 12Czechia36 cities11.1
- 13Hong Kong8 cities11.1
- 14United States736 cities10.8
- 15Slovakia26 cities10.2
- 16Switzerland9 cities10.1
- 17Singapore5 cities10.0
- 18Hungary8 cities9.6
- 19France130 cities9.3
- 20Austria28 cities8.7
+ 16 more countries, 8.7 µg/m³ and below
Not counted on this day, too few cities measured: Romania since 31 May 2023, Luxembourg since 28 May 2023, Australia since 27 May 2023 and 3 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.