This is old news now but here's what was in mexico for 15 ppm ulsd and the 500 ppm is colored for farm and marine as in the states.
The regulation specifies two different sulfur content limits for automotive diesel fuels: 15 ppm maximum for the larger metropolitan areas, the Mexico-US border and 11 transportation corridors, as well as for imported diesel; 500 ppm maximum for the rest of the country until December 31, 2018 after which the maximum sulfur content shall be 15 ppm for all of Mexico. The 3 metropolitan zones defined in the Regulation are: Mexico City Valley (ZMVM), Guadalajara Metropolitan Area (ZMG), Monterrey Metropolitan Area (ZMM). The Northern Border Zone (ZFN) comprises the municipalities bordering with the USA in the sates of Baja California (5), Sonora (22), Chihuahua (11), Coahuila (14), Nuevo Leon (6) and Tamaulipas (13). The 11 transportation corridors are formed by the highways that connect the largest industrial and Metropolitan areas:
México City to Mexicali
México City to Nuevo Laredo
San Luis Potosí to Durango
México City to Tampico
México City to Merida
Minatitlán to Oaxaca
Highways to Guatemala
México City to Lázaro Cárdenas
México City to Acapulco
México City to Matamoros
México City to Monterrey
https://www.dieselnet.com/standards/mx/fuel.php#y2016