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 Aug 2023: Pakistan 36.4 µg/m³, India 31.2 µg/m³ and Chile 31.1 µg/m³.
- 1Pakistan4 cities36.4
- 2India5 cities31.2
- 3Chile43 cities31.1
- 4China3 cities23.4
- 5Peru4 cities19.9
- 6Martinique3 cities18.0
- 7Mexico44 cities, was 1216.2
- 8Thailand11 cities16.1
- 9Malta4 cities15.7
- 10Singapore5 cities14.5
- 11Serbia3 cities13.7
- 12Slovakia27 cities13.1
- 13Czechia36 cities12.9
- 14Greece7 cities12.0
- 15Poland69 cities11.6
- 16Italy22 cities, was 2611.3
- 17North Macedonia7 cities10.4
- 18Romania7 cities10.3
- 19Hong Kong13 cities10.2
- 20Hungary7 cities10.0
+ 16 more countries, 9.0 µg/m³ and below
- 29United States755 cities7.2
Not counted on this day, too few cities measured: Luxembourg since 17 Aug 2023, Reunion since 9 Aug 2023, Lithuania since 16 Jul 2023 and The Netherlands since 24 Jun 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.