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 Apr 2026: Laos 65.2 µg/m³, Pakistan 37.7 µg/m³ and India 37.5 µg/m³.
- 1Laos3 cities65.2
- 2Pakistan14 cities37.7
- 3India232 cities37.5
- 4Kazakhstan4 cities28.2
- 5Thailand84 cities28.2
- 6Chile46 cities26.4
- 7Hong Kong12 cities24.2
- 8Peru6 cities24.1
- 9Taiwan44 cities19.2
- 10Mexico46 cities17.2
- 11Malta4 cities16.0
- 12South Korea141 cities15.1
- 13Serbia8 cities13.6
- 14North Macedonia13 cities12.7
- 15Senegal4 cities11.9
- 16Malawi5 cities11.0
- 17Brazil6 cities10.3
- 18Greece8 cities, was 1210.0
- 19Italy27 cities10.0
- 20Romania27 cities9.9
+ 29 more countries, 9.4 µg/m³ and below
- 40United States862 cities5.7
Not counted on this day, too few cities measured: Czechia since 23 Apr 2026, Poland since 16 Apr 2026, Ghana since 8 Apr 2026 and 2 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.