New Delhi: India’s leading GSM-based mobile operators added 6.2 million new subscribers in January, an industry body said on Monday, maintaining rapid expansion in the world’s fastest-growing wireless market.

Growth outpaced December, when 5.7 million customers were added, data from the Cellular Operators’ Association of India (COAI) showed.

Both figures exclude Reliance Communications Ltd , India’s No. 2 mobile firm, which operates mainly on the CDMA platform but has a limited and growing GSM presence.

It is yet to release its additions for January but in December signed up a total of 1.6 million new users across both technologies to take its base to nearly 41 million.

Total GSM users, excluding Reliance, rose to 178.4 million in January, COAI said.

India’s mobile market is booming thanks to call rates as low as one US cent a minute, the availability of cheap handsets and the expansion of networks to smaller towns and rural areas.

Still, only about a quarter of the population has a phone, and the government has a target of 500 million phones by 2010.

Bharti Airtel Ltd, India’s top mobile operator, led the signings, adding 2.3 million subscribers in January to take its mobile customer base to 57.4 million.

Vodafone Essar Ltd, controlled by Britain’s Vodafone, added 1.3 million users in the month, to take its subscriber base to 41.1 million, the association said.

State-owned Bharat Sanchar Nigam Ltd added 1 million users in January, taking its total to 33.7 million. Idea Cellular gained 900,658 subscribers, and now has 22 million users.