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 Apr 2026: Laos 117.1 µg/m³, Pakistan 38.6 µg/m³ and India 33.0 µg/m³.
- 1Laos3 cities117.1
- 2Pakistan13 cities38.6
- 3India235 cities33.0
- 4Thailand82 cities33.0
- 5Chile45 cities26.2
- 6Peru6 cities23.7
- 7Malta5 cities21.3
- 8Kazakhstan4 cities19.4
- 9Mexico54 cities17.8
- 10Serbia8 cities17.6
- 11Taiwan43 cities16.6
- 12South Korea140 cities15.2
- 13Poland60 cities14.5
- 14Senegal4 cities14.5
- 15Italy34 cities13.0
- 16Czechia7 cities12.5
- 17Hong Kong13 cities12.4
- 18North Macedonia15 cities12.2
- 19Slovakia39 cities11.2
- 20Romania27 cities11.1
+ 29 more countries, 10.8 µg/m³ and below
- 42United States855 cities6.1
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.