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 28 May 2023: Pakistan 38.7 µg/m³, China 34.1 µg/m³ and India 31.3 µg/m³.
- 1Pakistan4 cities38.7
- 2China3 cities34.1
- 3India5 cities31.3
- 4Chile45 cities30.2
- 5Thailand10 cities, was 7724.9
- 6Mexico13 cities, was 4719.7
- 7Serbia3 cities, was 2115.1
- 8Italy31 cities13.2
- 9Belgium41 cities13.0
- 10Slovakia26 cities12.8
- 11Poland58 cities12.1
- 12Czechia35 cities11.4
- 13Greece7 cities11.1
- 14Hungary8 cities11.0
- 15Malta3 cities11.0
- 16France128 cities10.9
- 17Lithuania3 cities10.7
- 18Germany197 cities10.5
- 19Switzerland9 cities10.2
- 20Singapore5 cities10.2
+ 12 more countries, 9.9 µg/m³ and below
- 25United States733 cities8.2
Not counted on this day, too few cities measured: Luxembourg since 28 May 2023, Australia since 27 May 2023, Hong Kong since 27 May 2023 and 8 more countries.
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.