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 15 Mar 2025: San Luis de la Paz 23.3 µg/m³, Irapuato 21.0 µg/m³ and León de los Aldama 18.9 µg/m³.
- 1San Luis de la PazGuanajuato23.3
- 2IrapuatoGuanajuato21.0
- 3León de los AldamaGuanajuato18.9
- 4TijuanaBaja California18.6
- 5CelayaGuanajuato17.2
- 6GuanajuatoGuanajuato15.2
- 7SalamancaGuanajuato14.6
- 8AbasoloGuanajuato14.2
- 9San Miguel de AllendeGuanajuato13.4
- 10Heroica MatamorosTamaulipas11.9
Not counted on this day, too few days measured: Mexico City since 27 Feb 2025, Silao de la Victoria since 26 Feb 2025, Nogales since 16 Feb 2025 and 4 more cities.
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.