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 30 days to 11 Apr 2026: Laos 81.4 µg/m³, Kazakhstan 44.5 µg/m³ and Pakistan 38.4 µg/m³.
- 1Laos3 cities81.4
- 2Kazakhstan4 cities44.5
- 3Pakistan12 cities38.4
- 4India240 cities34.8
- 5Thailand84 cities30.5
- 6South Korea141 cities25.3
- 7Peru6 cities23.2
- 8Chile47 cities22.1
- 9Ghana3 cities20.2
- 10Serbia4 cities19.2
- 11Taiwan44 cities17.7
- 12Poland59 cities17.6
- 13Mexico53 cities16.8
- 14North Macedonia14 cities15.7
- 15Hong Kong13 cities15.6
- 16Bosnia and Herzegovina5 cities14.9
- 17Latvia4 cities14.4
- 18Romania27 cities14.2
- 19Slovakia42 cities13.1
- 20Hungary13 cities12.4
+ 28 more countries, 11.8 µg/m³ and below
- 42United States871 cities6.5
Not counted on this day, too few cities measured: Philippines since 8 Apr 2026, Kyrgyzstan since 5 Apr 2026 and Spain since 18 Feb 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.