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 4 Apr 2024: Laos 84.7 µg/m³, India 46.8 µg/m³ and Pakistan 42.6 µg/m³.
- 1Laos3 cities84.7
- 2India5 cities46.8
- 3Pakistan4 cities42.6
- 4China4 cities36.0
- 5Malta4 cities28.8
- 6Thailand84 cities, was 7826.8
- 7Chile43 cities22.6
- 8South Korea127 cities21.0
- 9Taiwan43 cities21.0
- 10Hong Kong11 cities20.1
- 11Bosnia and Herzegovina5 cities18.4
- 12Mexico20 cities18.4
- 13Greece6 cities17.4
- 14Czechia37 cities17.3
- 15Latvia4 cities16.5
- 16Poland77 cities16.5
- 17Slovenia12 cities16.4
- 18Lithuania4 cities14.6
- 19Hungary10 cities, was 1014.2
- 20North Macedonia8 cities13.1
+ 26 more countries, 11.6 µg/m³ and below
- 37United States786 cities5.5
Not counted on this day, too few cities measured: Slovakia since 4 Apr 2024, Montenegro since 22 Mar 2024, Austria since 13 Mar 2024 and 4 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.