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 10 Apr 2023: India 41.8 µg/m³, China 37.3 µg/m³ and Thailand 36.6 µg/m³.
- 1India3 cities41.8
- 2China3 cities37.3
- 3Thailand58 cities36.6
- 4Serbia21 cities33.3
- 5Pakistan4 cities33.1
- 6Chile45 cities25.4
- 7Mexico45 cities20.8
- 8South Africa7 cities19.2
- 9Hong Kong12 cities17.3
- 10Czechia30 cities16.2
- 11Bulgaria6 cities15.2
- 12Romania7 cities15.1
- 13Poland29 cities15.0
- 14Hungary7 cities14.0
- 15Belgium37 cities13.9
- 16Slovakia25 cities13.1
- 17The Netherlands30 cities12.9
- 18Italy14 cities12.2
- 19Austria19 cities12.1
- 20Germany185 cities11.6
+ 15 more countries, 11.6 µg/m³ and below
- 29United States688 cities6.8
Not counted on this day, too few cities measured: Laos since 9 Apr 2023, Singapore since 8 Apr 2023, Brazil since 7 Apr 2023 and 8 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.