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 17 Nov 2023: India 114.3 µg/m³, Pakistan 83.7 µg/m³ and China 23.5 µg/m³.
- 1India4 cities114.3
- 2Pakistan3 cities83.7
- 3China3 cities23.5
- 4North Macedonia7 cities23.3
- 5Chile38 cities, was 4318.0
- 6Thailand9 cities16.3
- 7Hong Kong13 cities13.8
- 8Mexico42 cities13.3
- 9Serbia3 cities13.2
- 10Singapore5 cities13.2
- 11Romania7 cities11.2
- 12Lithuania4 cities11.1
- 13Bulgaria6 cities10.5
- 14Italy21 cities10.2
- 15Hungary9 cities9.7
- 16Czechia30 cities9.0
- 17Belgium41 cities8.6
- 18Greece9 cities8.5
- 19Slovakia26 cities8.0
- 20United States759 cities8.0
+ 14 more countries, 7.9 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 15 Nov 2023, 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.