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 26 Aug 2023: Pakistan 41.4 µg/m³, India 25.6 µg/m³ and Chile 23.2 µg/m³.
- 1Pakistan4 cities41.4
- 2India5 cities25.6
- 3Chile43 cities23.2
- 4Malta4 cities22.3
- 5China3 cities18.1
- 6Serbia3 cities17.6
- 7Slovakia25 cities17.3
- 8Greece7 cities17.2
- 9Italy14 cities17.1
- 10Czechia25 cities15.6
- 11North Macedonia6 cities15.2
- 12Switzerland8 cities14.1
- 13Thailand11 cities14.1
- 14Hungary7 cities13.8
- 15Romania4 cities13.3
- 16Bulgaria6 cities12.7
- 17Mexico13 cities12.2
- 18United States757 cities11.2
- 19Austria29 cities11.1
- 20Singapore5 cities11.0
+ 11 more countries, 10.8 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 22 Aug 2023, Australia since 21 Aug 2023, Hong Kong since 21 Aug 2023 and 5 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.