My friend is living in Mexico and he was telling me about this in an email the other day. Since the right-wing govenment won the election all prices have been going up: gasoline, electricity, milk, chicken, eggs, and now, finally, tortillas. That was like the straw that broke the camel's back because for the poorest families that's how they get a lot of their nutrients, not to mention it's somewhat symbolic of Mexican culture.
People are hella pissed. A bunch of tortilla delivery men charged in a govenment building on their motorcycles in protest, and they fought with the cops for the whole afternoon.