Roberto Rojas told me a few years ago that 3c is very popular there.When you go to a pool hall most of the tables are 3c with a few pocket tables in the back.They have to be carefull how many flyers they send out for a tournament or there will be more people than seats.We have some very good Mexican players here in Arizona.Three cushion seems to be popular in every country but the U.S.A.
Many billiard rooms are private clubs, and sometimes labeled as athletic or game clubs. Just ask around, I'm sure you'll find many places in Mexico City. It's a very popular game in Mexico.