New Delhi: GSM mobile subscriber base of six telecom operators marginally increased to 77.41 crore in May with net addition of 44 lakh new customers, as per data released by industry body COAI. Telecommunication towers “The GSM subscriber increased by 0.44 million in May 2016, 0.06 per cent increase from previous month” with maximum subscriber addition of 21.2lakh coming from telecom major Bharti Airtel. Vodafone followed Airtel in terms...