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 8 Aug 2023: Chile 40.7 µg/m³, Pakistan 31.3 µg/m³ and Peru 27.0 µg/m³.
- 1Chile43 cities40.7
- 2Pakistan4 cities31.3
- 3Peru3 cities27.0
- 4India5 cities24.5
- 5China3 cities21.6
- 6Thailand11 cities15.7
- 7Mexico45 cities, was 1213.6
- 8Malta4 cities13.5
- 9Greece7 cities11.2
- 10Singapore5 cities10.8
- 11Canada114 cities10.0
- 12Hong Kong13 cities9.2
- 13Bulgaria6 cities9.0
- 14United States754 cities8.7
- 15Romania6 cities8.4
- 16Serbia3 cities8.0
- 17North Macedonia5 cities7.8
- 18Portugal15 cities6.8
- 19Spain75 cities, was 956.5
- 20Martinique3 cities6.4
+ 18 more countries, 6.3 µg/m³ and below
Not counted on this day, too few cities measured: Lithuania since 16 Jul 2023, The Netherlands since 24 Jun 2023, Norway since 14 Jun 2023 and South Africa since 14 Jun 2023.
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.