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 Apr 2026: Laos 105.8 µg/m³, Pakistan 41.4 µg/m³ and India 36.9 µg/m³.
- 1Laos3 cities105.8
- 2Pakistan14 cities41.4
- 3India215 cities36.9
- 4Thailand84 cities29.4
- 5Chile45 cities26.2
- 6Kazakhstan4 cities25.0
- 7Hong Kong12 cities23.9
- 8Peru6 cities23.4
- 9Taiwan44 cities19.6
- 10Mexico46 cities19.0
- 11Malta5 cities17.2
- 12Serbia8 cities15.9
- 13South Korea141 cities15.7
- 14Senegal4 cities15.7
- 15North Macedonia13 cities15.0
- 16Czechia3 cities14.3
- 17Malawi5 cities13.6
- 18Hungary12 cities13.2
- 19Italy40 cities12.8
- 20Slovakia42 cities11.6
+ 29 more countries, 10.9 µg/m³ and below
- 43United States862 cities5.5
Not counted on this day, too few cities measured: Martinique since 19 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.