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 30 Mar 2023: China 46.9 µg/m³, Pakistan 32.9 µg/m³ and Thailand 26.0 µg/m³.
- 1China3 cities46.9
- 2Pakistan4 cities32.9
- 3Thailand77 cities26.0
- 4Chile43 cities24.6
- 5Mexico52 cities23.5
- 6Peru5 cities15.4
- 7South Africa11 cities14.6
- 8Brazil13 cities14.2
- 9Hong Kong11 cities12.8
- 10Greece7 cities12.3
- 11Poland63 cities11.5
- 12Romania7 cities10.9
- 13Slovakia25 cities10.4
- 14Czechia24 cities9.7
- 15Bulgaria7 cities9.6
- 16Italy20 cities9.0
- 17Singapore5 cities8.9
- 18Hungary7 cities8.7
- 19Spain85 cities8.0
- 20Ireland4 cities8.0
+ 14 more countries, 6.6 µg/m³ and below
- 23United States687 cities6.5
Not counted on this day, too few cities measured: Sweden since 29 Mar 2023, Kosovo since 28 Mar 2023, Luxembourg since 26 Mar 2023 and 8 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.