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 23 Feb 2024: Pakistan 98.9 µg/m³, India 71.9 µg/m³ and China 50.5 µg/m³.
- 1Pakistan4 cities98.9
- 2India5 cities71.9
- 3China3 cities50.5
- 4North Macedonia9 cities44.5
- 5Montenegro3 cities38.3
- 6Serbia18 cities, was 337.6
- 7Thailand74 cities, was 936.6
- 8Italy38 cities30.0
- 9Romania10 cities19.0
- 10Chile45 cities18.9
- 11Greece9 cities18.3
- 12Hong Kong13 cities18.0
- 13Bulgaria6 cities17.8
- 14Peru6 cities17.2
- 15Poland78 cities15.4
- 16South Africa8 cities15.4
- 17Slovakia42 cities14.9
- 18Mexico13 cities, was 4413.2
- 19Hungary10 cities13.1
- 20Latvia4 cities12.3
+ 22 more countries, 11.9 µg/m³ and below
- 36United States783 cities6.8
Not counted on this day, too few cities measured: Reunion since 20 Jan 2024 and Malta since 6 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.