Mobile Number Portability was introduced across the country on January 2011.
"On 29th May 2014, the number of subscribers who have successfully ported their mobile numbers using MNP facility has reached 100 million mark," Telecom Regulatory Authority of India said in a statement.
The number accounts for about 11 per cent of the total mobile subscriber base in the country which stood at 904.51 million as on March 31.
Trai had prescribed a porting charge of Rs 19, which is among the lowest in the world.
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In 2011, the porting request rejection rate was around 40 per cent which has been brought down to 11 per cent now. In the process, Trai has issued a number of directions and orders to the telecom service providers.
Financial disincentives worth about Rs 8 crore have also been levied on various service providers wherever they have been found in violation of MNP regulations on account of wrongful rejection of porting requests, it said.