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 8 Jun 2025: Chile 60.9 µg/m³, Pakistan 44.1 µg/m³ and Peru 30.7 µg/m³.
- 1Chile46 cities60.9
- 2Pakistan4 cities44.1
- 3Peru5 cities30.7
- 4India204 cities29.9
- 5Canada112 cities18.5
- 6South Korea139 cities17.9
- 7Mexico42 cities16.8
- 8Thailand78 cities15.2
- 9Serbia38 cities14.2
- 10Japan570 cities12.1
- 11Italy11 cities, was 2611.8
- 12Greece5 cities11.2
- 13Slovakia40 cities11.0
- 14Romania11 cities10.7
- 15United States826 cities10.0
- 16Latvia4 cities9.9
- 17New Zealand7 cities9.8
- 18Hong Kong13 cities9.6
- 19Poland73 cities9.2
- 20Lithuania4 cities9.0
+ 22 more countries, 8.1 µg/m³ and below
Not counted on this day, too few cities measured: Ireland since 8 Jun 2025, Kosovo since 3 Jun 2025, Czechia since 2 Jun 2025 and 2 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.