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 12 Aug 2025: San Francisco Tlalcilalcalpan 24.5 µg/m³, Santiaguito Tlalcilalcalli 24.5 µg/m³ and Xonacatlán 23.9 µg/m³.
- 1San Francisco TlalcilalcalpanMéxico24.5
- 2Santiaguito TlalcilalcalliMéxico24.5
- 3XonacatlánMéxico23.9
- 4TuxtlaChiapas23.4
- 5Atotonilco de TulaHidalgo20.1
- 6San Antonio la IslaMéxico20.0
- 7San Salvador TizatlalliMéxico20.0
- 8GarcíaNuevo León19.4
- 9SaltilloCoahuila19.0
- 10Tepeji del Río de OcampoHidalgo18.0
- 11Ciudad Benito JuárezNuevo León18.0
- 12Santa CatarinaNuevo León17.4
- 13Naucalpan de JuárezMéxico17.2
- 14ApizacoTlaxcala16.9
- 15León de los AldamaGuanajuato16.2
- 16MonterreyNuevo León15.2
- 17CelayaGuanajuato15.0
- 18MexicaliBaja California14.9
- 19Mexico CityMexico City14.6
- 20SalamancaGuanajuato14.4
+ 25 more cities, 13.7 µg/m³ and below
Not counted on this day, too few days measured: San Miguel de Allende since 12 Aug 2025, Tlaxcala since 7 Aug 2025, La Providencia Siglo XXI since 6 Aug 2025 and 11 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.