With the intervention of Telecom Regulator Authority of India (Trai), Hutch and Idea Cellular have withdrawn differential tariffs for calls made to the mobile networks of BSNL and MTNL."Idea and Hutch subscribers had to pay higher charges for calling MTNL and BSNL mobile GSM networks," Trai said.Hutch and Idea, in their tariff schemes, had classified subscribers using private GSM networks as a separate class to apply differential tariffs."Such classification is arbitrary and inconsistent with the provisions of telecom tariff orders," Trai added.