The Mafia does actually provide real waste-management services, also in Italy at large scale as far as I know. They do engage in racketeering to ensure that th

The Mafia does actually provide real waste-management services, also in Italy at large scale as far as I know. They do engage in racketeering to ensure that they own all the contracts in a certain region, and compete for territory, but they do often actually go and collect the waste, it's not just a front. And I think they did in the Sopranos too, although it was not explicitly depicted as far as I remember, just off-hand references. The illegal part is in how they get rid of it. Often they take on high-value contracts for toxic waste products that are complex to handle in a compliant manner, and they just dump it wherever.