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 10 Aug 2026: Mérida 42.8 µg/m³, San Luis Potosí 28.6 µg/m³ and Tuxtla 26.7 µg/m³.
- 1MéridaYucatán42.8
- 2San Luis PotosíSan Luis Potosí28.6
- 3TuxtlaChiapas26.7
- 4Ciudad General EscobedoNuevo León23.2
- 5Atotonilco de TulaHidalgo22.1
- 6Santa CatarinaNuevo León21.4
- 7MexicaliBaja California20.9
- 8Parque Industrial Ciudad MitrasNuevo León20.6
- 9Naucalpan de JuárezMéxico20.3
- 10Ciudad NezahualcoyotlMéxico19.5
- 11TijuanaBaja California19.4
- 12AguascalientesAguascalientes19.0
- 13Silao de la VictoriaGuanajuato18.6
- 14PueblaPuebla18.3
- 15MonterreyNuevo León17.9
- 16Ciudad ApodacaNuevo León17.9
- 17GuadalajaraJalisco17.1
- 18CelayaGuanajuato17.1
- 19Mexico CityMexico City16.6
- 20SalamancaGuanajuato16.6
+ 27 more cities, 16.5 µg/m³ and below
Not counted on this day, too few days measured: San Marcos since 8 Aug 2026, Hacienda Santa Fe since 21 Jul 2026, La Paz since 12 Jul 2026 and 5 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.