Telecom operator Idea Cellular has added the maximum number of subscribers at 3.32 million due to mobile number portability (MNP) followed by Vodafone (2.89 million) and Airtel (1.21 million) as on March 31, 2012.

"Idea Cellular received 9.29 million port-in requests compared to 5.97 million port-out requests, while 11.04 million users wanted to join Vodafone as compared to 8.15 million users who decided to opt out from its network," Telecom Minister Kapil Sibal has informed Parliament.

About 9.61 million Airtel subscribers requested port-out using MNP while 10.82 million opted to join it.

MNP service was introduced by the government in January 2011 to enable customers change their telecom service provider without changing their existing number.

Reliance Communications (GSM) received 3.14 million port-out requests compared to 1.79 million subscribers wishing to join the network. On the other hand, its CDMA services received 1.72 million port-out requests as against 0.24 million port-in requests.

Tata Teleservices lost 3.40 million subscribers compared to 2.89 million additions for its GSM service, while its CDMA business gained 0.09 million users, losing 1.30 million subscribers in the said period.

State-run BSNL (GSM) had 2.45 million port-out requests compared to 1.68 million port-in applications. MTNL, which operates in Delhi and Mumbai circles, had 0.13 million port-out requests compared to 0.03 million applications wishing to join the network.

Telecom Regulatory Authority of India (Trai) and the Department of Telecom (DoT) have received a total 26,325 complaints regarding rejection of MNP requests by mobile companies since its launch till March 31, 2012, Sibal added.

"Field units of DoT, Telecom Enforcement Resource and Monitoring (TERM) cells, received 20,509 complaints while Trai received 5,816 complaints," he said.

Of all the complaints received by TERM cells, 20,452 have been resolved, he added.

As per the MNP regulations, requests are to be settled in seven days except in J&K, Assam and North East for which the period is 15 days.

The government has so far issued notices to Bharti Airtel, Idea, Loop, Reliance and Vodafone for violating compliance of MNP regulations, Sibal said.