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 14 Apr 2024: Laos 59.1 µg/m³, China 46.3 µg/m³ and Thailand 38.6 µg/m³.
- 1Laos3 cities59.1
- 2China4 cities46.3
- 3Thailand78 cities38.6
- 4India5 cities37.0
- 5Pakistan4 cities37.0
- 6Peru5 cities28.2
- 7Chile46 cities24.5
- 8Taiwan42 cities22.5
- 9South Korea140 cities20.2
- 10Mexico12 cities18.6
- 11Hong Kong8 cities18.4
- 12Malta5 cities13.9
- 13Serbia24 cities13.9
- 14North Macedonia9 cities12.5
- 15Italy35 cities, was 3912.3
- 16Slovakia39 cities12.0
- 17Greece4 cities11.7
- 18Romania6 cities11.7
- 19Poland78 cities11.5
- 20Czechia38 cities10.9
+ 26 more countries, 10.7 µg/m³ and below
- 38United States787 cities5.6
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.