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 21 Jun 2024: Chile 28.3 µg/m³, China 26.3 µg/m³ and India 24.7 µg/m³.
- 1Chile42 cities28.3
- 2China4 cities26.3
- 3India4 cities24.7
- 4Peru14 cities21.3
- 5South Korea141 cities16.6
- 6Serbia16 cities14.3
- 7Italy12 cities, was 3813.6
- 8Bosnia and Herzegovina5 cities13.2
- 9Malta5 cities13.1
- 10North Macedonia9 cities13.0
- 11Slovakia39 cities12.3
- 12New Zealand5 cities11.9
- 13Thailand67 cities11.7
- 14Slovenia12 cities11.5
- 15Singapore5 cities11.3
- 16Greece7 cities10.6
- 17Hungary9 cities10.3
- 18Mexico4 cities, was 1210.1
- 19Japan554 cities9.4
- 20Bulgaria8 cities9.3
+ 21 more countries, 8.9 µg/m³ and below
- 23United States791 cities8.0
Not counted on this day, too few cities measured: Luxembourg since 20 Jun 2024, Pakistan since 18 Jun 2024, Switzerland since 6 Jun 2024 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.