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 22 May 2026: Chile 53.9 µg/m³, India 34.1 µg/m³ and Pakistan 30.0 µg/m³.
- 1Chile45 cities53.9
- 2India220 cities34.1
- 3Pakistan15 cities30.0
- 4Peru6 cities26.2
- 5Mexico48 cities20.5
- 6Kazakhstan4 cities16.0
- 7South Korea128 cities15.1
- 8New Zealand6 cities14.2
- 9Malawi5 cities13.6
- 10Senegal3 cities13.4
- 11Laos3 cities12.5
- 12Thailand81 cities11.6
- 13Brazil6 cities11.3
- 14Japan571 cities10.9
- 15Serbia8 cities10.3
- 16Taiwan44 cities10.1
- 17Hong Kong13 cities8.6
- 18North Macedonia13 cities8.6
- 19Malta5 cities8.6
- 20Greece10 cities7.8
+ 29 more countries, 7.8 µg/m³ and below
- 32United States849 cities6.3
Not counted on this day, too few cities measured: Slovenia since 12 May 2026, Lithuania since 7 May 2026, Poland since 16 Apr 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.