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 30 Oct 2023: India 64.9 µg/m³, Pakistan 62.1 µg/m³ and China 36.4 µg/m³.
- 1India4 cities64.9
- 2Pakistan4 cities62.1
- 3China3 cities36.4
- 4Chile41 cities21.6
- 5Thailand10 cities20.8
- 6Singapore5 cities19.9
- 7Malta4 cities15.9
- 8Serbia3 cities15.8
- 9North Macedonia7 cities14.9
- 10Greece9 cities14.0
- 11Italy30 cities12.0
- 12Czechia35 cities11.0
- 13Mexico11 cities, was 3710.9
- 14Hungary6 cities10.8
- 15Romania7 cities10.5
- 16Slovakia27 cities9.9
- 17Bulgaria6 cities9.3
- 18Austria30 cities9.0
- 19Switzerland8 cities8.4
- 20Spain96 cities8.3
+ 13 more countries, 7.9 µg/m³ and below
- 29United States768 cities6.5
Not counted on this day, too few cities measured: Australia since 23 Oct 2023, Hong Kong since 22 Oct 2023, Peru since 21 Oct 2023 and Poland since 8 Oct 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.