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 Feb 2024: India 71.4 µg/m³, Pakistan 69.8 µg/m³ and China 51.1 µg/m³.
- 1India5 cities71.4
- 2Pakistan3 cities69.8
- 3China3 cities51.1
- 4North Macedonia9 cities39.4
- 5Serbia18 cities36.4
- 6Montenegro3 cities36.3
- 7Thailand72 cities36.1
- 8Italy39 cities26.8
- 9Chile45 cities18.6
- 10Romania10 cities18.4
- 11Bulgaria6 cities18.3
- 12Greece9 cities18.3
- 13Peru6 cities17.7
- 14Hong Kong13 cities16.9
- 15Poland78 cities16.6
- 16Slovakia42 cities16.0
- 17Hungary10 cities13.4
- 18Mexico13 cities13.4
- 19Latvia4 cities12.6
- 20Czechia38 cities12.4
+ 23 more countries, 11.9 µg/m³ and below
- 36United States786 cities6.9
Not counted on this day, too few cities measured: Reunion since 20 Jan 2024. 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.