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 7 Jul 2023: Chile 37.9 µg/m³, Pakistan 30.6 µg/m³ and China 22.8 µg/m³.
- 1Chile46 cities37.9
- 2Pakistan4 cities30.6
- 3China3 cities22.8
- 4Greece8 cities15.0
- 5India5 cities12.9
- 6Thailand11 cities12.9
- 7Mexico9 cities12.2
- 8Serbia3 cities12.1
- 9Malta4 cities11.3
- 10Slovakia25 cities11.3
- 11Czechia36 cities10.7
- 12Romania7 cities10.7
- 13Bulgaria6 cities10.5
- 14United States737 cities10.0
- 15Hungary8 cities9.8
- 16Canada102 cities9.7
- 17Luxembourg3 cities9.5
- 18Italy30 cities9.4
- 19Lithuania4 cities9.0
- 20North Macedonia6 cities8.2
+ 13 more countries, 7.8 µg/m³ and below
Not counted on this day, too few cities measured: Martinique since 3 Jul 2023, Peru since 3 Jul 2023, The Netherlands since 24 Jun 2023 and 7 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.