SmogRank / Episodes / Mexico
Southern Mexico, 1 January 2026
For 1 day, on 1 January 2026, 20 cities in Mexico had PM2.5 at least twice their usual for the time of year. The worst reading was Tlaquepaque, Jalisco, Mexico: 182.0 µg/m³ on 1 January, about 3.2× its usual 56.9.
Likely New Year fireworks It came on the night of 31 December, when smoke from fireworks often fills the air over many cities at once.
Cities reached 20 in 1 country
Days 1 1 January 2026
Worst day 1 January 20 cities counted
Furthest above usual 6.2× Irapuato
Day by day
Play 1 January 20 cities at twice their usual or more
Celaya Salamanca San Luis de la Paz Guanajuato Mixquiahuala de Juárez San Francisco Tlalcilalcalpan San Salvador Tizatlalli Naucalpan de Juárez Cuernavaca Tulancingo Zacatepec de Hidalgo San Martin Texmelucan de Labastida Tlaxcala Atlixco Santa Anita Santiago de Querétaro Tula de Allende Xonacatlán San Juan del Río Zapopan San Luis Potosí Tehuacán Mexico City Hacienda Santa Fe Tlaquepaque La Providencia Siglo XXI León de los Aldama Silao de la Victoria San Miguel de Allende Abasolo Aguascalientes Ciudad Nezahualcoyotl Puebla Guadalajara Irapuato 29 Dec 30 31 1 Jan 2 3 4 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Tlaquepaque Tlaquepaque, 29 December: 30.3 µg/m³ Tlaquepaque, 30 December: 36.2 µg/m³ Tlaquepaque, 31 December: 34.1 µg/m³ Tlaquepaque, 1 January: 182.0 µg/m³, 3.2× its usual 56.9 Tlaquepaque, 2 January: 71.4 µg/m³ Tlaquepaque, 3 January: 54.7 µg/m³ Tlaquepaque, 4 January: 55.5 µg/m³ Guadalajara Guadalajara, 29 December: 26.5 µg/m³ Guadalajara, 30 December: 18.8 µg/m³ Guadalajara, 31 December: 23.0 µg/m³ Guadalajara, 1 January: 175.0 µg/m³, 5.8× its usual 30.1 Guadalajara, 2 January: 43.0 µg/m³ Guadalajara, 3 January: 35.7 µg/m³ Guadalajara, 4 January: 39.4 µg/m³ Hacienda Santa Fe Hacienda Santa Fe, 29 December: 33.9 µg/m³ Hacienda Santa Fe, 30 December: 30.8 µg/m³ Hacienda Santa Fe, 31 December: 57.2 µg/m³ Hacienda Santa Fe, 1 January: 138.0 µg/m³, 3.1× its usual 44.2 Hacienda Santa Fe, 2 January: 37.2 µg/m³ Hacienda Santa Fe, 3 January: 53.0 µg/m³ Hacienda Santa Fe, 4 January: 41.5 µg/m³ Ciudad Nezahualcoyo… Ciudad Nezahualcoyotl, 29 December: 24.2 µg/m³ Ciudad Nezahualcoyotl, 30 December: 9.8 µg/m³ Ciudad Nezahualcoyotl, 31 December: 32.8 µg/m³ Ciudad Nezahualcoyotl, 1 January: 132.0 µg/m³, 4.5× its usual 29.2 Ciudad Nezahualcoyotl, 2 January: no reading Ciudad Nezahualcoyotl, 3 January: 38.8 µg/m³ Ciudad Nezahualcoyotl, 4 January: 29.6 µg/m³ Aguascalientes Aguascalientes, 29 December: 40.2 µg/m³ Aguascalientes, 30 December: 107.0 µg/m³ Aguascalientes, 31 December: 208.0 µg/m³ Aguascalientes, 1 January: 130.0 µg/m³, 4.4× its usual 29.3 Aguascalientes, 2 January: 47.9 µg/m³ Aguascalientes, 3 January: 39.7 µg/m³ Aguascalientes, 4 January: 114.9 µg/m³ Irapuato Irapuato, 29 December: 31.3 µg/m³ Irapuato, 30 December: 6.0 µg/m³ Irapuato, 31 December: 35.6 µg/m³ Irapuato, 1 January: 117.0 µg/m³, 6.2× its usual 19.0 Irapuato, 2 January: 35.6 µg/m³ Irapuato, 3 January: 29.7 µg/m³ Irapuato, 4 January: 30.0 µg/m³ Puebla Puebla, 29 December: 19.0 µg/m³ Puebla, 30 December: 9.7 µg/m³ Puebla, 31 December: 13.9 µg/m³ Puebla, 1 January: 93.2 µg/m³, 5.0× its usual 18.8 Puebla, 2 January: 30.1 µg/m³ Puebla, 3 January: 25.1 µg/m³ Puebla, 4 January: 21.8 µg/m³ Xonacatlán Xonacatlán, 29 December: 31.8 µg/m³ Xonacatlán, 30 December: 24.7 µg/m³ Xonacatlán, 31 December: 44.6 µg/m³ Xonacatlán, 1 January: 85.4 µg/m³, 2.5× its usual 33.8 Xonacatlán, 2 January: 32.0 µg/m³ Xonacatlán, 3 January: 36.8 µg/m³ Xonacatlán, 4 January: 35.3 µg/m³ San Luis Potosí San Luis Potosí, 29 December: 26.4 µg/m³ San Luis Potosí, 30 December: 20.7 µg/m³ San Luis Potosí, 31 December: 35.0 µg/m³ San Luis Potosí, 1 January: 84.0 µg/m³, 3.0× its usual 27.6 San Luis Potosí, 2 January: 30.1 µg/m³ San Luis Potosí, 3 January: 32.0 µg/m³ San Luis Potosí, 4 January: 28.3 µg/m³ Silao de la Victoria Silao de la Victoria, 29 December: 17.6 µg/m³ Silao de la Victoria, 30 December: 8.8 µg/m³ Silao de la Victoria, 31 December: 25.4 µg/m³ Silao de la Victoria, 1 January: 77.9 µg/m³, 3.9× its usual 20.1 Silao de la Victoria, 2 January: 31.6 µg/m³ Silao de la Victoria, 3 January: 34.5 µg/m³ Silao de la Victoria, 4 January: 25.5 µg/m³ Mexico City Mexico City, 29 December: 17.8 µg/m³ Mexico City, 30 December: 9.2 µg/m³ Mexico City, 31 December: 28.7 µg/m³ Mexico City, 1 January: 68.0 µg/m³, 3.1× its usual 22.2 Mexico City, 2 January: no reading Mexico City, 3 January: 28.5 µg/m³ Mexico City, 4 January: 22.8 µg/m³ Zapopan Zapopan, 29 December: 13.8 µg/m³ Zapopan, 30 December: 12.0 µg/m³ Zapopan, 31 December: 13.4 µg/m³ Zapopan, 1 January: 62.9 µg/m³, 2.6× its usual 24.3 Zapopan, 2 January: 19.0 µg/m³ Zapopan, 3 January: 21.5 µg/m³ Zapopan, 4 January: 25.9 µg/m³ León de los Aldama León de los Aldama, 29 December: 21.5 µg/m³ León de los Aldama, 30 December: 8.1 µg/m³ León de los Aldama, 31 December: 16.7 µg/m³ León de los Aldama, 1 January: 60.4 µg/m³, 3.5× its usual 17.2 León de los Aldama, 2 January: 28.8 µg/m³ León de los Aldama, 3 January: 29.1 µg/m³ León de los Aldama, 4 January: 22.0 µg/m³ Abasolo Abasolo, 29 December: 25.3 µg/m³ Abasolo, 30 December: 6.4 µg/m³ Abasolo, 31 December: 21.7 µg/m³ Abasolo, 1 January: 59.8 µg/m³, 4.3× its usual 13.9 Abasolo, 2 January: 27.5 µg/m³ Abasolo, 3 January: 25.0 µg/m³ Abasolo, 4 January: 20.1 µg/m³ La Providencia Sigl… La Providencia Siglo XXI, 29 December: 18.2 µg/m³ La Providencia Siglo XXI, 30 December: 4.5 µg/m³ La Providencia Siglo XXI, 31 December: 19.2 µg/m³ La Providencia Siglo XXI, 1 January: 55.5 µg/m³, 3.4× its usual 16.4 La Providencia Siglo XXI, 2 January: 15.3 µg/m³ La Providencia Siglo XXI, 3 January: 19.9 µg/m³ La Providencia Siglo XXI, 4 January: 17.0 µg/m³ San Miguel de Allen… San Miguel de Allende, 29 December: 13.7 µg/m³ San Miguel de Allende, 30 December: 5.9 µg/m³ San Miguel de Allende, 31 December: 12.3 µg/m³ San Miguel de Allende, 1 January: 47.8 µg/m³, 4.1× its usual 11.6 San Miguel de Allende, 2 January: 21.2 µg/m³ San Miguel de Allende, 3 January: 20.9 µg/m³ San Miguel de Allende, 4 January: 15.6 µg/m³ Tehuacán Tehuacán, 29 December: 16.0 µg/m³ Tehuacán, 30 December: 5.4 µg/m³ Tehuacán, 31 December: 5.6 µg/m³ Tehuacán, 1 January: 43.7 µg/m³, 3.1× its usual 14.0 Tehuacán, 2 January: 21.0 µg/m³ Tehuacán, 3 January: 21.5 µg/m³ Tehuacán, 4 January: 17.7 µg/m³ Tula de Allende Tula de Allende, 29 December: no reading Tula de Allende, 30 December: 7.6 µg/m³ Tula de Allende, 31 December: 33.7 µg/m³ Tula de Allende, 1 January: 37.4 µg/m³, 2.4× its usual 15.3 Tula de Allende, 2 January: 18.3 µg/m³ Tula de Allende, 3 January: 20.3 µg/m³ Tula de Allende, 4 January: 18.9 µg/m³ Santiago de Queréta… Santiago de Querétaro, 29 December: 14.0 µg/m³ Santiago de Querétaro, 30 December: 3.9 µg/m³ Santiago de Querétaro, 31 December: 18.3 µg/m³ Santiago de Querétaro, 1 January: 34.2 µg/m³, 2.4× its usual 14.1 Santiago de Querétaro, 2 January: 22.6 µg/m³ Santiago de Querétaro, 3 January: 26.1 µg/m³ Santiago de Querétaro, 4 January: 14.2 µg/m³ San Juan del Río San Juan del Río, 29 December: 13.5 µg/m³ San Juan del Río, 30 December: 5.7 µg/m³ San Juan del Río, 31 December: 12.7 µg/m³ San Juan del Río, 1 January: 33.0 µg/m³, 2.6× its usual 12.7 San Juan del Río, 2 January: 16.3 µg/m³ San Juan del Río, 3 January: 19.8 µg/m³ San Juan del Río, 4 January: 14.7 µg/m³ 29 Dec 30 31 1 Jan 2 3 4 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Irapuato Guanajuato, Mexico 1 1 January 19.0 6.2× Guadalajara Jalisco, Mexico 1 1 January 30.1 5.8× Puebla Puebla, Mexico 1 1 January 18.8 5.0× Ciudad Nezahualcoyotl México, Mexico 1 1 January 29.2 4.5× Aguascalientes Aguascalientes, Mexico 1 1 January 29.3 4.4× Abasolo Guanajuato, Mexico 1 1 January 13.9 4.3× San Miguel de Allende Guanajuato, Mexico 1 1 January 11.6 4.1× Silao de la Victoria Guanajuato, Mexico 1 1 January 20.1 3.9× León de los Aldama Guanajuato, Mexico 1 1 January 17.2 3.5× La Providencia Siglo XXI Hidalgo, Mexico 1 1 January 16.4 3.4× Tlaquepaque Jalisco, Mexico 1 1 January 56.9 3.2× Hacienda Santa Fe Jalisco, Mexico 1 1 January 44.2 3.1× Mexico City Mexico City, Mexico 1 1 January 22.2 3.1× Tehuacán Puebla, Mexico 1 1 January 14.0 3.1× San Luis Potosí San Luis Potosí, Mexico 1 1 January 27.6 3.0× Zapopan Jalisco, Mexico 1 1 January 24.3 2.6× San Juan del Río Querétaro, Mexico 1 1 January 12.7 2.6× Xonacatlán México, Mexico 1 1 January 33.8 2.5× Tula de Allende Hidalgo, Mexico 1 1 January 15.3 2.4× Santiago de Querétaro Querétaro, Mexico 1 1 January 14.1 2.4×
Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.
Against other episodes in Mexico
The largest of 16 episodes in Mexico since our records began, by cities reached.
Southern Mexico, 1 January 2026 20 Southern United States and Mexico, June 2023 17 Southern Mexico, June 2024 16 Southern Mexico, January 2024 14 Southern Mexico, 5 to 9 January 2026 12 Northern Mexico and United States, May 2025 12 Southern Mexico, December 2023 10 Southern Mexico, June 2023 10 Hidalgo, Puebla and Querétaro, Mexico, November 2025 9 Guanajuato, México and Mexico City, Mexico, December 2024 9 Southern United States and Mexico, April 2024 9 Northern Mexico and United States, March and April 2025 8 Bars: cities reached; colour: the level of the episode's highest daily reading. All 16 .
Use this page SmogRank, Southern Mexico, 1 January 2026: 20 cities with PM2.5 at twice their usual or more, 1 January 2026, smogrank.com/episodes/2026-01-01-southern-mexico (accessed 4 October 2026).
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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
