Why does the Mafia get involved in hauling garbage? - Slate Magazine:
Organized crime appears to have a hand in trash collection all over the world, from Naples to Tony Soprano's northern New Jersey. Why are gangsters always hauling garbage?
It's Mob Economics 101: Find a business that's easy to enter and lucrative to control. Criminal organizations make lots of money from drugs, human trafficking, and counterfeit goods, but creating a monopoly on garbage collection is attractive because the business itself is legal, and public contracts return big profits.
Something similar seems to have happened to things like public transport, for example (dare one say it?) the taxi "industry" in South Africa.