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 19 Jun 2025: Pakistan 51.1 µg/m³, Chile 36.4 µg/m³ and India 24.1 µg/m³.
- 1Pakistan5 cities51.1
- 2Chile42 cities36.4
- 3India216 cities24.1
- 4Peru6 cities23.5
- 5New Zealand10 cities17.7
- 6South Korea140 cities16.3
- 7Serbia39 cities12.4
- 8Brazil46 cities12.1
- 9Mexico47 cities10.2
- 10Hungary4 cities, was 410.1
- 11Japan560 cities9.9
- 12Thailand74 cities9.8
- 13Bulgaria5 cities9.4
- 14Poland72 cities9.1
- 15Austria36 cities9.0
- 16Hong Kong13 cities8.4
- 17The Netherlands22 cities8.1
- 18Lithuania4 cities7.5
- 19Australia41 cities7.3
- 20United States820 cities7.1
+ 5 more countries, the next at 7.0 µg/m³
Not counted on this day, too few cities measured: Spain since 17 Jun 2025, Latvia since 17 Jun 2025, Romania since 17 Jun 2025 and 20 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.