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 20 Oct 2023: India 66.7 µg/m³, Pakistan 42.8 µg/m³ and Thailand 27.9 µg/m³.
- 1India4 cities66.7
- 2Pakistan4 cities42.8
- 3Thailand10 cities27.9
- 4China3 cities25.1
- 5Chile46 cities21.5
- 6Serbia3 cities21.1
- 7Singapore5 cities19.2
- 8Malta4 cities15.8
- 9North Macedonia7 cities14.3
- 10Czechia35 cities14.1
- 11Romania7 cities12.9
- 12Hungary8 cities12.7
- 13Greece9 cities12.1
- 14Austria30 cities11.8
- 15Slovakia26 cities11.7
- 16Mexico11 cities, was 4211.6
- 17Italy29 cities10.3
- 18Bulgaria6 cities9.5
- 19Japan528 cities9.5
- 20Germany60 cities8.1
+ 13 more countries, 7.5 µg/m³ and below
- 27United States757 cities5.4
Not counted on this day, too few cities measured: Martinique since 18 Oct 2023, Hong Kong since 17 Oct 2023, Peru since 17 Oct 2023 and 3 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.