GSM telecom operators added 6.5 million subscribers in April, taking the total user base to 670.57 million.
The GSM subscriber base was 664.08 million in March.
Leading telecom operator Bharti Airtel added 2.01 million users, highest in April, taking its total subscriber base to 183.29 million, according to the data released by the Cellular Operators Association of India (COAI).
It had a market share of 27.33 per cent by April-end.
Aditya Birla group firm Idea Cellular, with 17.03 per cent market share, added 1.48 million new subscribers, taking its subscriber base to 114.20 million.
Uninor, which has seen a significant growth in user base in the previous months, added 1.12 million new customers in April. Its user base was at 43.55 million by April-end.
Aircel, which had lost customers last month too, added 1.01 million new users to take its base to 63.58 million.
Vodafone, with a market share of 22.56 per cent, added 0.81 million customers taking its subscriber base to 151.28 million.
State-owned telecom firm BSNL did not see any additions during the month. MTNL also lost 0.1 million customers. The subscriber base of BSNL and MTNL stood at 94.67 million and 5.48 million, respectively.
Videocon added 0.15 million new customers taking its total base to 6.10 million.
Operators like Uninor and Videocon, whose licences have been cancelled by the Supreme Court in its February order, saw over two per cent growth in their subscriber additions.
Others like S Tel and Etisalat DB did not saw any new user additions. These companies have already announced shutting down of services and are now helping their users move to other operators through MNP.
Sistema Shyam TeleServices (SSTL), which operates under MTS brand and whose licence was also cancelled by the apex court, added 0.20 million customers in April taking its total customer base to 16.05 million.