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 4 Nov 2023: India 71.2 µg/m³, Pakistan 70.4 µg/m³ and China 41.5 µg/m³.
- 1India4 cities71.2
- 2Pakistan4 cities70.4
- 3China3 cities41.5
- 4Thailand10 cities23.0
- 5Chile23 cities21.6
- 6Singapore5 cities18.4
- 7Serbia3 cities14.9
- 8Malta4 cities14.7
- 9North Macedonia7 cities14.6
- 10Greece9 cities14.0
- 11Hungary6 cities10.8
- 12Italy25 cities10.8
- 13Mexico11 cities, was 3710.7
- 14Romania7 cities10.7
- 15Czechia33 cities10.5
- 16Slovakia27 cities9.3
- 17Japan527 cities8.9
- 18Bulgaria6 cities8.7
- 19Austria30 cities8.4
- 20Martinique3 cities7.5
+ 13 more countries, 7.4 µg/m³ and below
- 28United States769 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.