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 25 Apr 2023: China 56.3 µg/m³, India 50.5 µg/m³ and Pakistan 35.6 µg/m³.
- 1China3 cities56.3
- 2India3 cities50.5
- 3Pakistan4 cities35.6
- 4Thailand39 cities34.7
- 5Chile45 cities25.7
- 6Mexico41 cities22.4
- 7Hong Kong7 cities15.9
- 8Poland63 cities13.5
- 9Czechia29 cities12.6
- 10Greece8 cities11.7
- 11Romania7 cities11.7
- 12Hungary8 cities11.4
- 13Slovakia25 cities11.3
- 14Bulgaria6 cities10.6
- 15Belgium37 cities10.2
- 16Italy16 cities9.5
- 17The Netherlands31 cities8.8
- 18United Kingdom48 cities8.6
- 19Spain89 cities8.3
- 20Germany185 cities8.0
+ 13 more countries, 7.9 µg/m³ and below
- 25United States683 cities7.1
Not counted on this day, too few cities measured: South Africa since 25 Apr 2023, Peru since 24 Apr 2023, Kosovo since 2 Apr 2023 and 6 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.