The only legitimate way of gambling in India is through horse racing. The search for the reason behind this exception (betting on any other sport is illegal) ended up in a very bizarre answer that it was a skilful activity. I don't know how any skill helps in gambling in horse racing. My presumption is that the colonial tradition of betting in horse racing has continued to flourish, may be with the same laws.
But the irony of the gambling issue in India is the search for this legalised betting resulted in a page which has advertisements endorsed to bet in other sports