SmogRank / History / City race
Cities, worst air first, day by day
Each measured city's average over the 30 days to every day since January 2023, worst first. Find your own city to follow it through the race, or keep to one country.
The worst cities for PM2.5 over the 30 days to 27 May 2024: N'Djamena 174.0 µg/m³, Coyhaique 130.9 µg/m³ and Santa María 103.8 µg/m³.
- 1N'DjamenaChad174.0
- 2CoyhaiqueChile130.9
- 3Santa MaríaPeru103.8
- 4NacimientoChile99.8
- 5OsornoChile92.7
- 6LahorePakistan85.6
- 7DelhiIndia83.7
- 8HualpénChile80.5
- 9Puerto VarasChile76.9
- 10Chiang KhongThailand74.4
- 11Ban HouakhouaLaos74.4
- 12San CarlosChile74.2
- 13CuranilahueChile73.1
- 14DhakaBangladesh70.5
- 15LajaChile68.5
- 16ChillánChile66.5
- 17La UniónChile64.9
- 18KathmanduNepal61.2
- 19VillarricaChile60.5
- 20Los ÁngelesChile59.7
+ 2,769 more cities, 58.8 µg/m³ and below
Not counted on this day, too few days measured: Tlaquepaque since 23 May 2024.
Cities counted each day
A city's number is its average over the 30 days, shown only when 21 of them were measured (5 of 7 on the 7-day race), the same minimum as the 30- and 7-day boards. A city whose monitors go quiet fades out where it stood rather than sliding down, so a gap never reads as cleaner air. 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.