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 5 Mar 2024: India 66.0 µg/m³, Pakistan 65.3 µg/m³ and China 44.4 µg/m³.
- 1India5 cities66.0
- 2Pakistan3 cities65.3
- 3China3 cities44.4
- 4Thailand78 cities34.3
- 5North Macedonia9 cities30.9
- 6Montenegro3 cities30.4
- 7Serbia18 cities29.6
- 8Italy39 cities21.9
- 9Poland79 cities19.6
- 10Chile44 cities18.9
- 11Peru6 cities18.1
- 12Bulgaria6 cities17.8
- 13Romania10 cities17.6
- 14South Africa7 cities17.6
- 15Hong Kong13 cities16.9
- 16Greece9 cities16.1
- 17Slovakia42 cities15.1
- 18Hungary10 cities14.3
- 19Mexico13 cities14.3
- 20Czechia38 cities14.0
+ 23 more countries, 11.4 µg/m³ and below
- 38United States788 cities6.7
Not counted on this day, too few cities measured: Reunion since 20 Jan 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.