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 27 Apr 2023: China 55.7 µg/m³, India 49.6 µg/m³ and Pakistan 34.8 µg/m³.
- 1China3 cities55.7
- 2India3 cities49.6
- 3Pakistan4 cities34.8
- 4Thailand11 cities33.6
- 5Chile45 cities26.4
- 6Mexico41 cities22.2
- 7Poland58 cities13.5
- 8Czechia30 cities12.7
- 9Romania7 cities11.7
- 10Greece8 cities11.6
- 11Hungary8 cities11.6
- 12Slovakia25 cities11.5
- 13Belgium37 cities10.8
- 14Bulgaria6 cities10.5
- 15Italy16 cities9.6
- 16United Kingdom45 cities8.9
- 17The Netherlands31 cities8.8
- 18Austria23 cities8.3
- 19Germany185 cities8.3
- 20Spain89 cities8.3
+ 11 more countries, 7.8 µg/m³ and below
- 25United States682 cities7.2
Not counted on this day, too few cities measured: Australia since 26 Apr 2023, Hong Kong since 26 Apr 2023, South Africa since 25 Apr 2023 and 8 more countries. Days missing from the source archive fall in this window, so fewer countries are counted.
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.