SmogRank / Episodes / Mexico
Southern Mexico, 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× Aguascalientes
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 Zapopan San Juan del Río San Luis Potosí Hacienda Santa Fe Mexico City Tehuacán 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
Aguascalientes Aguascalientes, 29 December: 40.2 µg/m³, 1.4× usual Aguascalientes, 30 December: 107.0 µg/m³, 3.7× usual Aguascalientes, 31 December: 208.0 µg/m³, 7.1× usual Aguascalientes, 1 January: 130.0 µg/m³, 4.4× usual Aguascalientes, 2 January: 47.9 µg/m³, 1.6× usual Aguascalientes, 3 January: 39.7 µg/m³, 1.4× usual Aguascalientes, 4 January: 114.9 µg/m³, 3.9× usual Tula de Allende Tula de Allende, 29 December: no reading Tula de Allende, 30 December: 7.6 µg/m³, 0.5× usual Tula de Allende, 31 December: 33.7 µg/m³, 2.2× usual Tula de Allende, 1 January: 37.4 µg/m³, 2.4× usual Tula de Allende, 2 January: 18.3 µg/m³, 1.2× usual Tula de Allende, 3 January: 20.3 µg/m³, 1.3× usual Tula de Allende, 4 January: 18.9 µg/m³, 1.2× usual Tlaquepaque Tlaquepaque, 29 December: 30.3 µg/m³, 0.5× usual Tlaquepaque, 30 December: 36.2 µg/m³, 0.6× usual Tlaquepaque, 31 December: 34.1 µg/m³, 0.6× usual Tlaquepaque, 1 January: 182.0 µg/m³, 3.2× usual Tlaquepaque, 2 January: 71.4 µg/m³, 1.3× usual Tlaquepaque, 3 January: 54.7 µg/m³, 1.0× usual Tlaquepaque, 4 January: 55.5 µg/m³, 1.0× usual Guadalajara Guadalajara, 29 December: 26.5 µg/m³, 0.9× usual Guadalajara, 30 December: 18.8 µg/m³, 0.6× usual Guadalajara, 31 December: 23.0 µg/m³, 0.8× usual Guadalajara, 1 January: 175.0 µg/m³, 5.8× usual Guadalajara, 2 January: 43.0 µg/m³, 1.4× usual Guadalajara, 3 January: 35.7 µg/m³, 1.2× usual Guadalajara, 4 January: 39.4 µg/m³, 1.3× usual Hacienda Santa Fe Hacienda Santa Fe, 29 December: 33.9 µg/m³, 0.8× usual Hacienda Santa Fe, 30 December: 30.8 µg/m³, 0.7× usual Hacienda Santa Fe, 31 December: 57.2 µg/m³, 1.3× usual Hacienda Santa Fe, 1 January: 138.0 µg/m³, 3.1× usual Hacienda Santa Fe, 2 January: 37.2 µg/m³, 0.8× usual Hacienda Santa Fe, 3 January: 53.0 µg/m³, 1.2× usual Hacienda Santa Fe, 4 January: 41.5 µg/m³, 0.9× usual Ciudad Nezahualcoyo… Ciudad Nezahualcoyotl, 29 December: 24.2 µg/m³, 0.8× usual Ciudad Nezahualcoyotl, 30 December: 9.8 µg/m³, 0.3× usual Ciudad Nezahualcoyotl, 31 December: 32.8 µg/m³, 1.1× usual Ciudad Nezahualcoyotl, 1 January: 132.0 µg/m³, 4.5× usual Ciudad Nezahualcoyotl, 2 January: no reading Ciudad Nezahualcoyotl, 3 January: 38.8 µg/m³, 1.3× usual Ciudad Nezahualcoyotl, 4 January: 29.6 µg/m³, 1.0× usual Irapuato Irapuato, 29 December: 31.3 µg/m³, 1.6× usual Irapuato, 30 December: 6.0 µg/m³, 0.3× usual Irapuato, 31 December: 35.6 µg/m³, 1.9× usual Irapuato, 1 January: 117.0 µg/m³, 6.2× usual Irapuato, 2 January: 35.6 µg/m³, 1.9× usual Irapuato, 3 January: 29.7 µg/m³, 1.6× usual Irapuato, 4 January: 30.0 µg/m³, 1.6× usual Puebla Puebla, 29 December: 19.0 µg/m³, 1.0× usual Puebla, 30 December: 9.7 µg/m³, 0.5× usual Puebla, 31 December: 13.9 µg/m³, 0.7× usual Puebla, 1 January: 93.2 µg/m³, 5.0× usual Puebla, 2 January: 30.1 µg/m³, 1.6× usual Puebla, 3 January: 25.1 µg/m³, 1.3× usual Puebla, 4 January: 21.8 µg/m³, 1.2× usual Xonacatlán Xonacatlán, 29 December: 31.8 µg/m³, 0.9× usual Xonacatlán, 30 December: 24.7 µg/m³, 0.7× usual Xonacatlán, 31 December: 44.6 µg/m³, 1.3× usual Xonacatlán, 1 January: 85.4 µg/m³, 2.5× usual Xonacatlán, 2 January: 32.0 µg/m³, 0.9× usual Xonacatlán, 3 January: 36.8 µg/m³, 1.1× usual Xonacatlán, 4 January: 35.3 µg/m³, 1.0× usual San Luis Potosí San Luis Potosí, 29 December: 26.4 µg/m³, 1.0× usual San Luis Potosí, 30 December: 20.7 µg/m³, 0.7× usual San Luis Potosí, 31 December: 35.0 µg/m³, 1.3× usual San Luis Potosí, 1 January: 84.0 µg/m³, 3.0× usual San Luis Potosí, 2 January: 30.1 µg/m³, 1.1× usual San Luis Potosí, 3 January: 32.0 µg/m³, 1.2× usual San Luis Potosí, 4 January: 28.3 µg/m³, 1.0× usual Silao de la Victoria Silao de la Victoria, 29 December: 17.6 µg/m³, 0.9× usual Silao de la Victoria, 30 December: 8.8 µg/m³, 0.4× usual Silao de la Victoria, 31 December: 25.4 µg/m³, 1.3× usual Silao de la Victoria, 1 January: 77.9 µg/m³, 3.9× usual Silao de la Victoria, 2 January: 31.6 µg/m³, 1.6× usual Silao de la Victoria, 3 January: 34.5 µg/m³, 1.7× usual Silao de la Victoria, 4 January: 25.5 µg/m³, 1.3× usual Mexico City Mexico City, 29 December: 17.8 µg/m³, 0.8× usual Mexico City, 30 December: 9.2 µg/m³, 0.4× usual Mexico City, 31 December: 28.7 µg/m³, 1.3× usual Mexico City, 1 January: 68.0 µg/m³, 3.1× usual Mexico City, 2 January: no reading Mexico City, 3 January: 28.5 µg/m³, 1.3× usual Mexico City, 4 January: 22.8 µg/m³, 1.0× usual Zapopan Zapopan, 29 December: 13.8 µg/m³, 0.6× usual Zapopan, 30 December: 12.0 µg/m³, 0.5× usual Zapopan, 31 December: 13.4 µg/m³, 0.6× usual Zapopan, 1 January: 62.9 µg/m³, 2.6× usual Zapopan, 2 January: 19.0 µg/m³, 0.8× usual Zapopan, 3 January: 21.5 µg/m³, 0.9× usual Zapopan, 4 January: 25.9 µg/m³, 1.1× usual León de los Aldama León de los Aldama, 29 December: 21.5 µg/m³, 1.3× usual León de los Aldama, 30 December: 8.1 µg/m³, 0.5× usual León de los Aldama, 31 December: 16.7 µg/m³, 1.0× usual León de los Aldama, 1 January: 60.4 µg/m³, 3.5× usual León de los Aldama, 2 January: 28.8 µg/m³, 1.7× usual León de los Aldama, 3 January: 29.1 µg/m³, 1.7× usual León de los Aldama, 4 January: 22.0 µg/m³, 1.3× usual Abasolo Abasolo, 29 December: 25.3 µg/m³, 1.8× usual Abasolo, 30 December: 6.4 µg/m³, 0.5× usual Abasolo, 31 December: 21.7 µg/m³, 1.6× usual Abasolo, 1 January: 59.8 µg/m³, 4.3× usual Abasolo, 2 January: 27.5 µg/m³, 2.0× usual Abasolo, 3 January: 25.0 µg/m³, 1.8× usual Abasolo, 4 January: 20.1 µg/m³, 1.4× usual La Providencia Sigl… La Providencia Siglo XXI, 29 December: 18.2 µg/m³, 1.1× usual La Providencia Siglo XXI, 30 December: 4.5 µg/m³, 0.3× usual La Providencia Siglo XXI, 31 December: 19.2 µg/m³, 1.2× usual La Providencia Siglo XXI, 1 January: 55.5 µg/m³, 3.4× usual La Providencia Siglo XXI, 2 January: 15.3 µg/m³, 0.9× usual La Providencia Siglo XXI, 3 January: 19.9 µg/m³, 1.2× usual La Providencia Siglo XXI, 4 January: 17.0 µg/m³, 1.0× usual San Miguel de Allen… San Miguel de Allende, 29 December: 13.7 µg/m³, 1.2× usual San Miguel de Allende, 30 December: 5.9 µg/m³, 0.5× usual San Miguel de Allende, 31 December: 12.3 µg/m³, 1.1× usual San Miguel de Allende, 1 January: 47.8 µg/m³, 4.1× usual San Miguel de Allende, 2 January: 21.2 µg/m³, 1.8× usual San Miguel de Allende, 3 January: 20.9 µg/m³, 1.8× usual San Miguel de Allende, 4 January: 15.6 µg/m³, 1.3× usual Tehuacán Tehuacán, 29 December: 16.0 µg/m³, 1.1× usual Tehuacán, 30 December: 5.4 µg/m³, 0.4× usual Tehuacán, 31 December: 5.6 µg/m³, 0.4× usual Tehuacán, 1 January: 43.7 µg/m³, 3.1× usual Tehuacán, 2 January: 21.0 µg/m³, 1.5× usual Tehuacán, 3 January: 21.5 µg/m³, 1.5× usual Tehuacán, 4 January: 17.7 µg/m³, 1.3× usual Santiago de Queréta… Santiago de Querétaro, 29 December: 14.0 µg/m³, 1.0× usual Santiago de Querétaro, 30 December: 3.9 µg/m³, 0.3× usual Santiago de Querétaro, 31 December: 18.3 µg/m³, 1.3× usual Santiago de Querétaro, 1 January: 34.2 µg/m³, 2.4× usual Santiago de Querétaro, 2 January: 22.6 µg/m³, 1.6× usual Santiago de Querétaro, 3 January: 26.1 µg/m³, 1.9× usual Santiago de Querétaro, 4 January: 14.2 µg/m³, 1.0× usual San Juan del Río San Juan del Río, 29 December: 13.5 µg/m³, 1.1× usual San Juan del Río, 30 December: 5.7 µg/m³, 0.4× usual San Juan del Río, 31 December: 12.7 µg/m³, 1.0× usual San Juan del Río, 1 January: 33.0 µg/m³, 2.6× usual San Juan del Río, 2 January: 16.3 µg/m³, 1.3× usual San Juan del Río, 3 January: 19.8 µg/m³, 1.6× usual San Juan del Río, 4 January: 14.7 µg/m³, 1.2× usual 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
Aguascalientes Aguascalientes, Mexico 1 31 December 29.3 7.1× 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× 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× Tehuacán Puebla, Mexico 1 1 January 14.0 3.1× Mexico City Mexico City, Mexico 1 1 January 22.2 3.1× San Luis Potosí San Luis Potosí, Mexico 1 1 January 27.6 3.0× San Juan del Río Querétaro, Mexico 1 1 January 12.7 2.6× Zapopan Jalisco, Mexico 1 1 January 24.3 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. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in Mexico
The largest of 12 episodes in Mexico since our records began, by cities reached.
Southern Mexico, January 2026 20 Southern United States and Mexico, June 2023 18 Southern Mexico, January 2026 12 Northern Mexico and United States, May 2025 12 Southern Mexico, December 2023 10 Guanajuato and Jalisco, Mexico, June 2023 10 Southern Mexico, January 2023 10 Hidalgo and Puebla, Mexico, November 2025 9 Southern United States and Mexico, March and April 2025 8 Guanajuato and Querétaro, Mexico, March 2025 8 Northern Mexico and United States, May 2023 8 Guanajuato and Jalisco, Mexico, May 2023 8 Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Southern Mexico, January 2026: 20 cities with PM2.5 at twice their usual or more, 1 January 2026, smogrank.com/episodes/2026-01-southern-mexico (accessed 2 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.
