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 16 Oct 2025: Pakistan 66.9 µg/m³, India 29.9 µg/m³ and Peru 29.2 µg/m³.
- 1Pakistan11 cities66.9
- 2India216 cities29.9
- 3Peru5 cities29.2
- 4Chile46 cities20.9
- 5Philippines3 cities17.7
- 6Ghana4 cities17.0
- 7Bosnia and Herzegovina5 cities14.2
- 8Serbia29 cities13.0
- 9North Macedonia10 cities11.5
- 10Taiwan45 cities11.4
- 11Mexico47 cities11.0
- 12Thailand70 cities10.5
- 13Poland68 cities10.0
- 14Hungary4 cities, was 129.9
- 15Brazil3 cities8.5
- 16Hong Kong13 cities8.4
- 17Martinique3 cities8.4
- 18Latvia4 cities8.2
- 19Romania11 cities8.2
- 20Australia22 cities8.0
+ 24 more countries, 8.0 µg/m³ and below
- 36United States876 cities6.2
Not counted on this day, too few cities measured: Italy since 15 Oct 2025, Ireland since 13 Oct 2025, Estonia since 12 Oct 2025 and 4 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.