GSM telecom operators added 6.87 million subscribers in March, taking the total user base to 664.08 million.
The GSM subscriber base stood at 657.21 million at the end of February.
Leading operator Bharti Airtel added the most 2.5 million users in March, taking its total subscriber base to 181.28 million, according to the data released by the Cellular Operators Association of India (COAI).
It had a market share of 27.3% by March-end.
Rival Vodafone Essar, with a 22.66% market share, added 1.02 million new subscribers during the month, taking its subscriber to 150.47 million.
Uninor, which has seen significant growth in userbase in the previous months, added 1.29 million new customers in March. Its user base was at 42.43 million by March-end.
Aditya Birla group firm Idea Cellular added 2.01 million users during the month to take its total user base to 112.72 million.
Aircel lost 0.68 million customers during the month and its subscriber base was at 62.57 million.
Reliance Telecom added 59,829 new users to take its userbase to 31.84 million at the end of March.
State-run telecom firms BSNL and MTNL added 0.89 million and 62,399 million new users, respectively, taking their subscriber base to 94.67 million and 5.59 million, respectively.
Leading GSM operators seemed to have cornered a major chunk of users of the new telecom operators, which announced closing operations after the Supreme Court order cancelling their licences, through mobile number portability (MNP).
Operators such as S Tel, Etisalat DB and Loop Telecom have announced shutting down of services and are now helping their users move to other operators through MNP.
The Supreme Court in February cancelled 122 licences that were allotted in 2008.