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 19 Aug 2023: Pakistan 39.7 µg/m³, India 30.2 µg/m³ and Chile 29.2 µg/m³.
- 1Pakistan4 cities39.7
- 2India5 cities30.2
- 3Chile43 cities29.2
- 4China3 cities27.9
- 5Peru4 cities20.6
- 6Martinique3 cities19.5
- 7Thailand11 cities16.1
- 8Malta4 cities16.0
- 9Serbia3 cities15.2
- 10Mexico32 cities, was 1214.9
- 11Slovakia27 cities14.4
- 12Czechia35 cities13.6
- 13Singapore5 cities13.6
- 14Poland60 cities13.0
- 15Italy23 cities, was 2612.8
- 16Greece7 cities12.7
- 17North Macedonia7 cities12.1
- 18Hungary7 cities11.9
- 19Romania7 cities11.8
- 20Hong Kong12 cities11.7
+ 16 more countries, 10.1 µg/m³ and below
- 28United States754 cities8.0
Not counted on this day, too few cities measured: Luxembourg since 17 Aug 2023, Reunion since 9 Aug 2023, Lithuania since 16 Jul 2023 and The Netherlands since 24 Jun 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 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.