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 30 days to 21 Aug 2024: Chile 41.1 µg/m³, Pakistan 32.9 µg/m³ and China 22.0 µg/m³.
- 1Chile44 cities41.1
- 2Pakistan4 cities32.9
- 3China4 cities22.0
- 4Peru16 cities21.0
- 5India5 cities17.5
- 6Malta5 cities14.6
- 7Singapore5 cities14.4
- 8New Zealand5 cities14.3
- 9Italy9 cities13.1
- 10North Macedonia9 cities13.1
- 11Thailand17 cities13.0
- 12Martinique3 cities10.5
- 13Slovakia36 cities10.5
- 14Hong Kong13 cities10.2
- 15Serbia18 cities9.9
- 16South Korea140 cities9.8
- 17Japan556 cities9.0
- 18Poland74 cities9.0
- 19Belgium38 cities8.9
- 20Hungary9 cities8.9
+ 20 more countries, 8.9 µg/m³ and below
- 22United States800 cities8.8
Not counted on this day, too few cities measured: Greece since 21 Aug 2024, Ireland since 19 Aug 2024, Slovenia since 18 Aug 2024 and 5 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.