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 27 Nov 2023: Pakistan 115.8 µg/m³, India 112.0 µg/m³ and China 47.8 µg/m³.
- 1Pakistan3 cities115.8
- 2India4 cities112.0
- 3China3 cities47.8
- 4North Macedonia7 cities34.1
- 5Thailand11 cities29.3
- 6Serbia3 cities24.1
- 7Hong Kong13 cities22.8
- 8Chile39 cities, was 4318.3
- 9Romania7 cities17.0
- 10Mexico45 cities, was 1115.9
- 11Bulgaria6 cities15.2
- 12Greece8 cities12.5
- 13Italy22 cities12.1
- 14Hungary8 cities12.0
- 15Czechia27 cities11.1
- 16Slovakia26 cities10.3
- 17Brazil32 cities10.0
- 18Japan496 cities9.3
- 19Spain104 cities8.8
- 20Martinique3 cities8.7
+ 17 more countries, the next at 8.6 µg/m³
- 27United States751 cities6.7
Not counted on this day, too few cities measured: Ireland since 31 Oct 2023, Peru since 17 Oct 2023 and Poland since 1 Oct 2023.
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, Turkey and Iran, which publish only on their own websites. We are building the reader for China's network. The networks of Turkey and Iran don't answer requests from outside their countries, so we can't read them. Most cities there are missing from this board, not clean. Why.