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 19 Sep 2023: Pakistan 39.0 µg/m³, Chile 27.0 µg/m³ and Peru 27.0 µg/m³.
- 1Pakistan4 cities39.0
- 2Chile43 cities27.0
- 3Peru4 cities27.0
- 4India5 cities23.4
- 5China3 cities21.8
- 6Mexico40 cities15.2
- 7Singapore5 cities14.7
- 8Malta4 cities13.4
- 9Serbia3 cities13.4
- 10North Macedonia4 cities13.2
- 11Greece7 cities13.1
- 12Thailand11 cities13.1
- 13Czechia35 cities12.1
- 14Hungary9 cities11.7
- 15Slovakia27 cities11.5
- 16Italy28 cities11.3
- 17Bulgaria6 cities10.1
- 18Belgium41 cities9.6
- 19Hong Kong11 cities9.3
- 20Martinique3 cities9.3
+ 15 more countries, 8.9 µg/m³ and below
- 26United States763 cities8.5
Not counted on this day, too few cities measured: Poland since 21 Aug 2023, Reunion since 16 Aug 2023, Lithuania since 27 Jul 2023 and Luxembourg since 27 Jul 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.