SmogRank / History / City race
Cities in Mexico, 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 in Mexico for PM2.5 over the 30 days to 20 Jul 2023: Salamanca 19.4 µg/m³, Ciudad Juárez 19.2 µg/m³ and Celaya 18.9 µg/m³.
- 1SalamancaGuanajuato19.4
- 2Ciudad JuárezChihuahua19.2
- 3CelayaGuanajuato18.9
- 4León de los AldamaGuanajuato15.9
- 5IrapuatoGuanajuato14.6
- 6TijuanaBaja California14.4
- 7San Luis de la PazGuanajuato13.9
- 8Mexico CityMexico City13.5
- 9AbasoloGuanajuato12.7
- 10GuanajuatoGuanajuato12.3
- 11San Miguel de AllendeGuanajuato11.5
- 12NogalesSonora8.6
Not counted on this day, too few days measured: Ecatepec de Morelos since 9 Jul 2023, Tlaquepaque since 3 Jul 2023, Silao de la Victoria since 15 Jun 2023 and Naucalpan de Juárez since 28 May 2023. Days missing from the source archive fall in this window, so fewer countries are counted.
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.