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 18 Oct 2023: India 72.2 µg/m³, Pakistan 43.4 µg/m³ and China 34.3 µg/m³.
- 1India4 cities72.2
- 2Pakistan4 cities43.4
- 3China3 cities34.3
- 4Thailand10 cities24.7
- 5Serbia3 cities22.4
- 6Chile46 cities21.3
- 7Singapore5 cities20.1
- 8North Macedonia7 cities16.2
- 9Malta4 cities15.7
- 10Hungary8 cities13.3
- 11Greece9 cities11.8
- 12Romania7 cities11.8
- 13Czechia35 cities11.6
- 14Slovakia27 cities11.6
- 15Italy30 cities11.3
- 16Mexico11 cities, was 4211.0
- 17Bulgaria6 cities9.4
- 18Spain106 cities9.4
- 19Austria30 cities9.3
- 20Switzerland8 cities9.0
+ 12 more countries, 8.2 µg/m³ and below
- 28United States768 cities5.2
Not counted on this day, too few cities measured: Martinique since 18 Oct 2023, Australia since 17 Oct 2023, Hong Kong since 17 Oct 2023 and 4 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.