India's largest cellular services provider Bharti Tele-Ventures Ltd's customer base in Delhi has touched one million, an industry official said on Monday.

New Delhi-based Bharti, 16 per cent owned by Singapore Telecommunications, is also likely to make additional investments in the Delhi zone, India's largest cellular market, the official, who did not want to be identified, told Reuters.

The official did not give details.

Bharti has more than 3.1 million cellular users across 15 telecoms zones. It is the leading player in Delhi where at the end of April it had more than 938,000 users out of the city's total customer base of 1.85 million.

Bharti competes in Delhi with the Indian cellular unit of Hong Kong's Hutchison Whampoa conglomerate, state-run Mahanagar Telephone Nigam Ltd and Idea Cellular Ltd.

India's intensely competitive cellular industry, which has among the lowest call rates in the world, has more than 13.3 million customers.

Analysts say the user base is expected to grow by a million customers each month, including those opting for the rival limited mobility services.