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 12 Apr 2026: Laos 114.2 µg/m³, Pakistan 38.4 µg/m³ and Thailand 34.1 µg/m³.
- 1Laos3 cities114.2
- 2Pakistan13 cities38.4
- 3Thailand83 cities34.1
- 4India236 cities31.8
- 5Chile47 cities26.2
- 6Peru6 cities23.0
- 7Kazakhstan4 cities18.5
- 8Serbia8 cities17.7
- 9Mexico56 cities16.8
- 10Taiwan43 cities16.4
- 11South Korea140 cities15.1
- 12Czechia4 cities15.0
- 13Poland59 cities13.6
- 14Italy34 cities12.9
- 15Hong Kong13 cities12.8
- 16Senegal4 cities12.6
- 17North Macedonia15 cities12.5
- 18Romania26 cities11.0
- 19Slovakia31 cities10.3
- 20Greece5 cities9.8
+ 29 more countries, 9.7 µg/m³ and below
- 41United States857 cities5.8
Not counted on this day, too few cities measured: Ghana since 8 Apr 2026, Bosnia and Herzegovina since 6 Apr 2026, Philippines since 6 Apr 2026 and Kyrgyzstan since 25 Mar 2026.
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.