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 27 Dec 2023: Pakistan 127.7 µg/m³, India 113.4 µg/m³ and North Macedonia 44.9 µg/m³.
- 1Pakistan4 cities127.7
- 2India4 cities113.4
- 3North Macedonia7 cities44.9
- 4China3 cities43.4
- 5Serbia3 cities37.5
- 6Thailand9 cities33.2
- 7Bulgaria5 cities20.7
- 8Mexico44 cities, was 1120.5
- 9Hong Kong13 cities20.2
- 10Romania8 cities19.3
- 11Slovakia27 cities19.3
- 12Czechia34 cities19.1
- 13Italy23 cities17.4
- 14Chile40 cities17.3
- 15Greece9 cities17.2
- 16Hungary7 cities16.9
- 17Austria28 cities13.6
- 18Lithuania3 cities12.7
- 19Brazil34 cities10.7
- 20Belgium41 cities10.1
+ 17 more countries, the next at 9.8 µg/m³
- 28United States762 cities7.7
Not counted on this day, too few cities measured: Martinique since 8 Dec 2023.
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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.