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 Oct 2023: India 60.0 µg/m³, Pakistan 58.3 µg/m³ and China 30.7 µg/m³.
- 1India4 cities60.0
- 2Pakistan4 cities58.3
- 3China3 cities30.7
- 4Chile45 cities21.6
- 5Singapore5 cities20.8
- 6Thailand10 cities19.8
- 7Malta4 cities16.6
- 8Serbia3 cities16.4
- 9Greece8 cities14.6
- 10North Macedonia7 cities13.8
- 11Italy29 cities, was 412.7
- 12Czechia35 cities11.8
- 13Mexico11 cities, was 3711.1
- 14Hungary8 cities10.9
- 15Romania7 cities10.9
- 16Slovakia27 cities10.6
- 17Bulgaria6 cities9.7
- 18Austria30 cities9.3
- 19Switzerland8 cities9.0
- 20Spain76 cities8.8
+ 12 more countries, 8.4 µg/m³ and below
- 28United States768 cities6.6
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.