They are what remain of Carnival celebrations brought to Mexico City by the Spanish but subsequently suppressed by Inquisition authorities.
However the Mexican Inquisition, banned most of the traditions associated with it in Mexico City, forcing celebrations outside the historic center into what was the rural areas of the Valley of Mexico, including what is now the borough of Iztapalapa.
It went underground until after the Independence of Mexico and has since reappeared in various communities in Iztapalapa.
[1][3] The basic structure of Carnival celebrations are groups of dancers, most organized under the name of “comparsa” or krewe.
[1][3] One tradition related to carnival is “lunes de ahorcado” or Monday of the hanged.