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 6 Aug 2023: Chile 36.5 µg/m³, Pakistan 32.1 µg/m³ and Peru 26.5 µg/m³.
- 1Chile42 cities36.5
- 2Pakistan4 cities32.1
- 3Peru3 cities26.5
- 4China3 cities22.2
- 5India5 cities22.0
- 6Thailand11 cities14.5
- 7Malta4 cities14.0
- 8Mexico44 cities, was 1212.7
- 9Greece8 cities12.3
- 10Singapore5 cities11.2
- 11Bulgaria6 cities10.9
- 12Romania6 cities10.0
- 13Serbia3 cities9.1
- 14Canada114 cities8.8
- 15United States747 cities8.7
- 16Hong Kong12 cities8.6
- 17North Macedonia6 cities8.4
- 18Spain66 cities, was 956.7
- 19Hungary7 cities6.7
- 20Slovakia27 cities6.7
+ 17 more countries, 6.6 µg/m³ and below
Not counted on this day, too few cities measured: Italy since 28 Jul 2023, Lithuania since 16 Jul 2023, The Netherlands since 24 Jun 2023 and 2 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.