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 23 Nov 2023: Pakistan 148.7 µg/m³, India 91.3 µg/m³ and China 37.1 µg/m³.
- 1Pakistan4 cities148.7
- 2India4 cities91.3
- 3China3 cities37.1
- 4North Macedonia7 cities32.1
- 5Thailand9 cities30.6
- 6Serbia3 cities24.4
- 7Hong Kong13 cities19.7
- 8Chile39 cities, was 4318.4
- 9Mexico46 cities17.7
- 10Martinique3 cities16.8
- 11Romania7 cities15.2
- 12Bulgaria6 cities15.0
- 13Italy22 cities13.0
- 14Greece7 cities12.4
- 15Hungary8 cities12.4
- 16Slovakia26 cities10.1
- 17Czechia33 cities10.0
- 18Belgium41 cities9.6
- 19Lithuania4 cities9.5
- 20Austria29 cities8.7
+ 16 more countries, 8.4 µg/m³ and below
- 27United States761 cities6.9
Not counted on this day, too few cities measured: Ireland since 31 Oct 2023, Peru since 17 Oct 2023 and Poland since 1 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.