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 29 Nov 2023: Pakistan 116.7 µg/m³, India 107.2 µg/m³ and Thailand 30.5 µg/m³.
- 1Pakistan3 cities116.7
- 2India4 cities107.2
- 3Thailand11 cities30.5
- 4China3 cities28.2
- 5Hong Kong13 cities25.7
- 6North Macedonia7 cities22.9
- 7Serbia3 cities18.9
- 8Chile38 cities18.2
- 9Mexico44 cities, was 1114.4
- 10Romania7 cities14.0
- 11Bulgaria6 cities13.7
- 12Italy23 cities13.7
- 13Greece8 cities12.2
- 14Hungary6 cities11.6
- 15Slovakia26 cities11.6
- 16Czechia28 cities11.2
- 17France128 cities9.4
- 18Japan499 cities9.2
- 19Lithuania4 cities9.1
- 20Spain103 cities8.6
+ 16 more countries, 8.4 µg/m³ and below
- 25United States738 cities7.3
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.