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 24 Oct 2023: India 67.6 µg/m³, Pakistan 64.4 µg/m³ and China 30.8 µg/m³.
- 1India4 cities67.6
- 2Pakistan3 cities64.4
- 3China3 cities30.8
- 4Thailand10 cities28.5
- 5Chile43 cities21.2
- 6Malta4 cities16.6
- 7Serbia3 cities16.1
- 8Czechia36 cities15.6
- 9Romania7 cities15.5
- 10Singapore5 cities15.5
- 11North Macedonia7 cities14.2
- 12Greece9 cities12.9
- 13Mexico11 cities, was 4212.7
- 14Hungary6 cities12.6
- 15Austria30 cities12.1
- 16Slovakia24 cities12.0
- 17Italy27 cities9.3
- 18Bulgaria6 cities8.6
- 19Japan521 cities8.3
- 20Germany59 cities7.7
+ 14 more countries, 7.2 µg/m³ and below
- 24United States753 cities6.5
Not counted on this day, too few cities measured: Hong Kong since 17 Oct 2023, Peru since 17 Oct 2023, Poland since 1 Oct 2023 and 2 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.