SmogRank / World / Mexico / December 2025

Most people breathing unhealthy air in Mexico, December 2025

16 cities in Mexico measured at 2 or more places, ranked by how many people breathed unhealthy air on an average day over the 31 days. The most people breathing unhealthy air: Mexicali, Mexico, about 566K on an average day. A city needs measurements on 70% of the days to be ranked.

About 2.23M people in these 16 cities breathed unhealthy air on an average day of December 2025.

Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.

← Mexicali 566K 500K0
Every city in Mexico ranked for December 2025 with monitors in two or more places, one column each, ranked by people breathing unhealthy air: height is people on an average day, colour its average. Point at it to read a city; tap to open it.
  1. 1MexicaliBaja California
    566K
  2. 2GuadalajaraJalisco
    536K
  3. 3Mexico CityMexico City
    397K
  4. 4AguascalientesAguascalientes
    373K
  5. 5Ciudad NezahualcoyotlMéxico
    278K
  6. 6ZapopanJalisco
    47.6K
  7. 7Santa CatarinaNuevo León
    19.6K
  8. 8Ciudad General EscobedoNuevo León
    15.2K
  9. 9PueblaPuebla
    0
  10. 10TepicNayarit
    0
  11. 11CelayaGuanajuato
    0
  12. 12León de los AldamaGuanajuato
    0
  13. 13MonterreyNuevo León
    0
  14. 14Santiago de QuerétaroQuerétaro
    0
  15. 15Ciudad JuárezChihuahua
    0
  16. 16Victoria de DurangoDurango
    0
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales

All cities in the world, December 2025 · Mexico now

Regions

Aguascalientes 1Baja California 2Baja California Sur 1Chiapas 1Chihuahua 1Durango 1Guanajuato 8Hidalgo 3Jalisco 4México 4Mexico City 1Morelos 2Nayarit 1Nuevo León 7Puebla 3Querétaro 2Sonora 1Tamaulipas 1Yucatán 1

Ranked cities in each region, December 2025.

Use this board

SmogRank, most polluted cities in Mexico, by people breathing unhealthy air, PM2.5, December 2025, smogrank.com/mx/history/2025-12?by=people (accessed 7 Oct 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.