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 23 Aug 2024: Chile 35.2 µg/m³, Pakistan 32.2 µg/m³ and Brazil 31.9 µg/m³.
- 1Chile44 cities35.2
- 2Pakistan4 cities32.2
- 3Brazil34 cities31.9
- 4Peru14 cities23.4
- 5India5 cities20.3
- 6China4 cities17.2
- 7New Zealand5 cities13.2
- 8Hungary5 cities12.8
- 9Serbia12 cities12.7
- 10Thailand17 cities, was 912.3
- 11Singapore6 cities11.4
- 12Poland69 cities10.5
- 13South Korea140 cities9.9
- 14Hong Kong13 cities8.5
- 15Japan554 cities7.8
- 16United States804 cities7.4
- 17United Kingdom60 cities6.9
- 18The Netherlands20 cities6.6
- 19Mexico3 cities6.5
- 20Bulgaria5 cities6.3
+ 5 more countries, the next at 6.3 µg/m³
Not counted on this day, too few cities measured: Belgium since 17 Aug 2024, Switzerland since 17 Aug 2024, Germany since 17 Aug 2024 and 22 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, 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.