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 16 Jun 2025: Pakistan 46.7 µg/m³, Chile 41.2 µg/m³ and India 28.0 µg/m³.
- 1Pakistan5 cities46.7
- 2Chile45 cities41.2
- 3India219 cities28.0
- 4Peru6 cities25.4
- 5South Korea140 cities14.2
- 6Mexico41 cities14.2
- 7Serbia38 cities12.7
- 8New Zealand10 cities12.0
- 9Austria37 cities10.9
- 10Thailand76 cities10.8
- 11Bulgaria5 cities10.3
- 12Romania7 cities10.1
- 13Hungary10 cities, was 49.2
- 14United States824 cities9.0
- 15Poland72 cities8.9
- 16The Netherlands22 cities8.7
- 17Canada115 cities8.5
- 18Lithuania4 cities8.2
- 19Japan562 cities8.1
- 20United Kingdom66 cities7.6
+ 7 more countries, 7.5 µg/m³ and below
Not counted on this day, too few cities measured: Bosnia and Herzegovina since 9 Jun 2025, Belgium since 9 Jun 2025, Switzerland since 9 Jun 2025 and 17 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.