The people who own the biggest scam operations seem to know what authorities they need to bribe to ensure that they are left alone. In some cases, they might be one of the top contributors to a local economy and police are not going to fuck with companies that bring a sudden upswell of prosperity to their city, especially if they're taking bribes from them.

It seems as though someone has to fuck up and get the CBI (India's central law enforcement body, equivalent to the FBI) involved before they can reliably get their criminal enterprise stomped.

Between the bribes and simply bringing a sudden upswell of imported money to local economies, a lot of scam operations seemingly manage to get tacit immunity from their local law enforcement.