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 17 Apr 2024: Laos 56.0 µg/m³, India 37.8 µg/m³ and Thailand 35.2 µg/m³.
- 1Laos3 cities56.0
- 2India5 cities37.8
- 3Thailand81 cities35.2
- 4China4 cities34.2
- 5Pakistan4 cities29.9
- 6Chile46 cities24.3
- 7Peru6 cities22.7
- 8Taiwan43 cities22.7
- 9South Korea141 cities21.1
- 10Mexico10 cities20.0
- 11Hong Kong11 cities17.3
- 12Malta5 cities15.2
- 13Serbia24 cities15.1
- 14North Macedonia9 cities14.4
- 15Greece6 cities12.3
- 16Italy39 cities, was 3911.5
- 17Japan519 cities11.1
- 18Poland77 cities10.9
- 19Romania8 cities10.8
- 20Slovakia41 cities10.5
+ 26 more countries, 9.8 µg/m³ and below
- 37United States782 cities5.5
Not counted on this day, too few cities measured: Belgium since 13 Apr 2024, Montenegro since 22 Mar 2024, Austria since 13 Mar 2024 and 4 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.