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 24 Nov 2023: Pakistan 147.8 µg/m³, India 103.4 µg/m³ and China 39.5 µg/m³.
- 1Pakistan4 cities147.8
- 2India4 cities103.4
- 3China3 cities39.5
- 4North Macedonia7 cities33.9
- 5Thailand9 cities32.2
- 6Serbia3 cities29.4
- 7Hong Kong13 cities21.6
- 8Chile39 cities, was 4318.5
- 9Mexico45 cities16.8
- 10Bulgaria6 cities14.8
- 11Romania7 cities14.4
- 12Martinique3 cities13.9
- 13Italy22 cities13.5
- 14Hungary8 cities12.9
- 15Greece7 cities12.8
- 16Slovakia26 cities10.6
- 17Czechia29 cities10.2
- 18Japan509 cities9.2
- 19Lithuania4 cities8.9
- 20Spain107 cities8.5
+ 16 more countries, 8.4 µg/m³ and below
- 27United States750 cities6.6
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.