NEW DELHI, INDIA: Indian GSM mobile operators added 8.3 million users in May, taking the total user base to 306.45 million, data from the Cellular Operators' Association of India said.

The pace of monthly additions slowed for a second month, down from 8.97 million in April and 10.8 million in March, hit mainly by slowing additions by state-run Bharat Sanchar Nigam Ltd.

BSNL saw its subscribers additions slow to 453,582 in May less than half of April's 1.04 million April and less than one-fifth of record additions of 2.50 million in March.

Top mobile operator Bharti Airtel added 2.81 million mobile users in May to have a total of 99.5 million, while third-ranked Vodafone Essar signed up 2.54 million mobile users to boost its total to 74.1 million.

Fifth-ranked Idea Cellular gained 1.3 million mobile users to 45.5 million and Aircel added 1.1 million to have 20.7 million users at the end of May.

The data for May does not include Reliance Communications Ltd, India's second-largest mobile operator, which reports figures separately. But total GSM subscribers include Reliance's GSM users at the end of April.

Reliance Communications, which had 74.8 million subscribers at end-April, expanded its GSM mobile services to all the service areas of the country in January, but the majority of its customers are still on rival CDMA technology.

Tata Teleservices, in which Japan's NTT DoCoMo owns a 26 percent stake, also operates on CDMA and its monthly additions are reported separately. The company is launching GSM this month.