There is a big retail market for drugs in all Mexican cities . These stores . "tienditas ", are run out of businesses and houses in neighborhoods where cocaine , crack , heroin , meth , and marijuana can be purchased 24/7 . It is a very lucrative business for the cartels since they incorporated the local drug dealers who now are supplied by them and are de-facto employees . The dealers are expected to pay a percentage of their sales ( piso ) and are given protection by the cartel . Sometimes the cartel will just takeover an established dealer's "tiendita " through murder and intimidation and set up their business where they take all the profits. In American corporate speak , this is the typical " hostile takeover ".
I can tell you from first hand experience that local sales are growing and becoming more important. Tourists and locals. Waiters in restaurants sell, bouncers in bars sell. Where I live they park at particular intersections 24 hours a day, right in the neighborhoods throughout the area and people walk up or drive by. Terrible for the children. Everyone knows what's going on but no one acts. A friend who lives in an isolate ejido tells me most of the men there are users so it's not only the cities and towns. Treatment is almost absent. A meth addict with 5 or 6 little children comes to beg regularly, grinding her jaw in the typical manner. DIF took the kids for awhile but she now has them back. Pretty little girls will be for sale soon if not already. Another who stakes out a street corner washing windows sold her daughter's virginity for $130 USD. Daughter's baby grew up being used as a prop to garner sales from tourists. Daughter is now working the streets. Hazard a guess that there is NO local enforcement as local sales are certainly a protected cartel activity. Just another way to grind a peso out of the hide of the Mexican people.
You can write your congressman or call your local mayor or chief of police. I, as a non Mexican citizen can do little with the structure. I can and do as I am able on an individual basis, but of necessity I fly under the wire.
I believe that the use of illegal drugs is prevalent in most modern societies . Here , in the U.S. , I have had family , friends , co-workers and neighbors end up dead and/or incarcerated because they either trafficked illegal drugs or abused them to the point of committing crimes to support their drug habit . I have lived and traveled in Latin America ( lived in Mexico , Colombia , and Venezuela ) and have seen first hand the destruction caused by drug trafficking and drug abuse on the lives of its citizens . I have often heard some of my fellow Mexicans say that the can tolerate drug trafficking as long as the drugs are intended for the American drug market . This is a fallacy as Rubbertoe noted , since there is a growing out-of-control epidemic of drug abuse in Mexico and other Latin American countries where the drug cartels are based .