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 24 May 2026: Chile 61.3 µg/m³, India 35.7 µg/m³ and Pakistan 30.5 µg/m³.
- 1Chile44 cities61.3
- 2India223 cities35.7
- 3Pakistan15 cities30.5
- 4Peru6 cities26.7
- 5Mexico47 cities18.7
- 6Ghana3 cities17.2
- 7Kazakhstan4 cities16.8
- 8South Korea127 cities14.3
- 9New Zealand6 cities14.2
- 10Malawi5 cities13.3
- 11Laos3 cities12.9
- 12Thailand80 cities12.5
- 13Serbia8 cities11.1
- 14Senegal4 cities10.8
- 15Hong Kong13 cities9.7
- 16North Macedonia13 cities9.4
- 17The Netherlands37 cities9.3
- 18Japan570 cities9.0
- 19Lebanon3 cities8.5
- 20Slovakia41 cities8.5
+ 28 more countries, 8.4 µg/m³ and below
- 38United States835 cities5.4
Not counted on this day, too few cities measured: Czechia since 24 May 2026, Taiwan since 23 May 2026, Slovenia since 12 May 2026 and 3 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.