Negocios informales. They are everywhere in Mexico. Right in front of negocios formales. Blocking the door. Sometimes selling the same exact product. 25% cheaper. They have an association and strong community representatives. They pay gangsters for permission/protection and low level government slugs to look the other way. Most of what’s sold is black market stuff.
In Manila in the Philippines mostly Muslim Filipinos came to Manilla from other places and set up stalls over time right on public roadways so that a 3 lane road would have the sidewalk and one lane occupied by illegal vendors, the second lane for their parked cars and only one lane for traffic. This cancer gradually grew all over Manila. The vendors payed local officials rent, often more than what a real store would pay, and the real stores went vacant and became toilets for the vendors. Or they built their own toilets over sewer grates. Or they built on to the fronts of real stores, occupying the sidewalks so pedestrians had to walk in the street. My wife said this did not exist there at all when she left in the early 80's. With truly massive efforts they have been clearing it away slowly for the last few years.
If you can, stop it now before it gets out of hand. Where I live 15 vocal attendees at every televised town board meeting can get a lot done. The board sees a group in the audience and gets the message.
Here's coverage of street clearing in Manila - where it goes if left unchecked:
https://fb.watch/dVzAddvwgj/