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 29 Nov 2023: Pakistan 102.6 µg/m³, India 100.8 µg/m³ and China 36.3 µg/m³.
- 1Pakistan3 cities102.6
- 2India4 cities100.8
- 3China3 cities36.3
- 4Thailand9 cities26.2
- 5North Macedonia7 cities22.4
- 6Chile37 cities18.6
- 7Hong Kong13 cities17.7
- 8Serbia3 cities16.1
- 9Mexico39 cities15.4
- 10Romania7 cities12.1
- 11Greece8 cities12.0
- 12Bulgaria6 cities11.6
- 13Singapore5 cities11.0
- 14Hungary8 cities10.8
- 15Italy20 cities10.8
- 16Martinique3 cities10.6
- 17Slovakia27 cities9.8
- 18Lithuania4 cities9.6
- 19Japan514 cities9.5
- 20Czechia28 cities9.4
+ 14 more countries, 7.8 µg/m³ and below
- 21United States771 cities7.8
Not counted on this day, too few cities measured: Malta since 11 Nov 2023, Ireland since 6 Nov 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.