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 25 Oct 2023: Pakistan 58.1 µg/m³, India 57.4 µg/m³ and China 30.1 µg/m³.
- 1Pakistan4 cities58.1
- 2India4 cities57.4
- 3China3 cities30.1
- 4Chile44 cities21.2
- 5Singapore5 cities20.9
- 6Thailand10 cities19.5
- 7Serbia3 cities16.8
- 8Malta4 cities16.1
- 9Greece8 cities14.0
- 10North Macedonia7 cities13.7
- 11Italy29 cities, was 412.7
- 12Czechia35 cities12.4
- 13Romania7 cities11.5
- 14Hungary8 cities11.2
- 15Mexico10 cities, was 3711.1
- 16Slovakia27 cities11.0
- 17Bulgaria6 cities9.8
- 18Austria30 cities9.7
- 19Switzerland8 cities9.4
- 20Spain71 cities8.9
+ 12 more countries, 8.6 µg/m³ and below
- 28United States770 cities6.4
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.