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 21 May 2023: Pakistan 37.0 µg/m³, Chile 33.8 µg/m³ and India 30.1 µg/m³.
- 1Pakistan4 cities37.0
- 2Chile45 cities33.8
- 3India5 cities30.1
- 4Thailand11 cities, was 7727.8
- 5Mexico12 cities, was 4719.5
- 6Serbia3 cities, was 2115.1
- 7Greece7 cities12.8
- 8Singapore5 cities12.6
- 9Czechia35 cities12.1
- 10Bulgaria6 cities11.8
- 11Belgium41 cities10.9
- 12Luxembourg3 cities10.7
- 13Malta3 cities10.7
- 14Poland55 cities9.7
- 15Romania6 cities9.7
- 16Ireland4 cities9.4
- 17Germany194 cities9.0
- 18Slovakia26 cities9.0
- 19United States739 cities8.9
- 20Austria30 cities8.7
+ 13 more countries, 8.7 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 20 May 2023, Australia since 10 May 2023, China since 10 May 2023 and 7 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.