SmogRank / World / Mexico / January 2023

Most polluted cities in Mexico, January 2023

9 cities in Mexico ranked by their average PM2.5 over the 31 days. Worst: Celaya at 34.6 µg/m³, #48 of 1,225 cities in the world. Cleanest: Heroica Matamoros at 9.3. A city needs measurements on 70% of the days to be ranked.

OpenAQ's archive, where our readings come from, has almost none for 7 of these 31 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.

Mexico has 43 cities ranked over the last 30 days, but only 9 here: most of its monitors have no readings for January 2023 in OpenAQ's archive, where ours come from, or too few to rank. Cities missing from this board weren't clean, just not measured.

Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.

← Celaya 32% 30%0
Every city in Mexico ranked for January 2023, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1CelayaGuanajuato
    32%
  2. 2Ecatepec de MorelosMéxico
    22%
  3. 3TijuanaBaja California
    13%
  4. 4Mexico CityMexico City
    9%
  5. 5León de los AldamaGuanajuato
    4%
  6. 6NogalesSonora
    3%
  7. 7Ciudad JuárezChihuahua
    0%
  8. 8AbasoloGuanajuato
    0%
  9. 9Heroica MatamorosTamaulipas
    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, January 2023 · Mexico now

Regions

Baja California 1Chihuahua 1Guanajuato 3México 1Mexico City 1Sonora 1Tamaulipas 1

Ranked cities in each region, January 2023.

Use this board

SmogRank, most polluted cities in Mexico, PM2.5, January 2023, smogrank.com/mx/history/2023-01 (accessed 7 Oct 2026).

Download top 10 (PNG)

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.