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 24 Oct 2023: Pakistan 57.4 µg/m³, India 56.5 µg/m³ and China 28.6 µg/m³.
- 1Pakistan4 cities57.4
- 2India4 cities56.5
- 3China3 cities28.6
- 4Chile44 cities21.2
- 5Singapore5 cities21.0
- 6Thailand10 cities19.5
- 7Serbia3 cities16.4
- 8Malta4 cities15.5
- 9Mexico19 cities14.6
- 10Greece8 cities13.7
- 11North Macedonia7 cities13.4
- 12Italy30 cities, was 413.0
- 13Czechia36 cities12.4
- 14Romania7 cities11.5
- 15Hungary8 cities11.1
- 16Slovakia27 cities10.8
- 17Austria30 cities9.7
- 18Bulgaria6 cities9.7
- 19Switzerland8 cities9.4
- 20Spain69 cities8.9
+ 12 more countries, 8.6 µg/m³ and below
- 28United States771 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.