Following a directive from Trai, Hutch has stopped offering push-to-talk (PTT) services to subscribers with effect from March 9."Hutch has informed that they are suspending the service to current customers from all circles untill they obtain approval of the licensor, department of telecom (DoT), for this service," Trai said in a statement today.The company has also stopped advertising the service and were withdrawing all promotional materials, including banners and brochures, from the market, the statement said.Hutch had launched PTT as a value-added service to their subscribers without obtaining prior approval of DoT, Trai said.