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 13 Jun 2025: Chile 55.2 µg/m³, Pakistan 49.4 µg/m³ and India 32.4 µg/m³.
- 1Chile47 cities55.2
- 2Pakistan5 cities49.4
- 3India220 cities32.4
- 4Peru6 cities27.9
- 5Mexico43 cities17.7
- 6Canada110 cities17.1
- 7South Korea139 cities17.0
- 8Serbia38 cities14.8
- 9Thailand78 cities13.2
- 10Hungary4 cities, was 411.9
- 11Japan565 cities11.7
- 12Bulgaria5 cities9.7
- 13United States826 cities9.6
- 14Lithuania4 cities9.0
- 15Poland72 cities7.8
- 16United Kingdom63 cities7.6
- 17New Zealand10 cities7.6
- 18Taiwan45 cities7.5
- 19The Netherlands22 cities7.4
- 20Hong Kong13 cities6.1
+ 3 more countries, 4.4 µg/m³ and below
Not counted on this day, too few cities measured: Latvia since 13 Jun 2025, Romania since 13 Jun 2025, Austria since 9 Jun 2025 and 21 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.