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 15 Aug 2024: Chile 44.2 µg/m³, Pakistan 34.9 µg/m³ and China 22.6 µg/m³.
- 1Chile43 cities44.2
- 2Pakistan4 cities34.9
- 3China4 cities22.6
- 4Peru16 cities21.0
- 5India4 cities17.0
- 6New Zealand5 cities15.5
- 7Singapore5 cities15.1
- 8Malta5 cities14.1
- 9North Macedonia9 cities13.9
- 10Italy11 cities13.2
- 11Thailand59 cities11.9
- 12Greece6 cities11.7
- 13Slovakia41 cities11.1
- 14Martinique3 cities10.8
- 15Serbia18 cities10.4
- 16Japan558 cities9.7
- 17Hong Kong13 cities9.5
- 18Romania9 cities9.3
- 19Mexico3 cities9.2
- 20South Korea140 cities9.1
+ 25 more countries, 9.1 µg/m³ and below
- 24United States802 cities8.7
Not counted on this day, too few cities measured: Czechia since 7 Aug 2024, Spain since 24 Jul 2024 and Bosnia and Herzegovina since 20 Jul 2024.
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.