The Prime Minister Dr Manmohan Singh on Friday said that air waves for starting the third generation telephony service will be sold shortly at market determined prices.Speaking at a Telecom Conference in New Delhi, he expressed happiness that auction of spectrum for 3G and broadband wireless services will be conducted shortly.He said, the government has decided that this spectrum will be allocated at market determined prices rather than administered one.Auction of 3G spectrum is slated to commence on 14th January, but has been plagued by differences between Defence and Telecom Ministries over vacation of spectrum for civilian use.Dr Singh also predicted that India, which already has nearly 488 million mobile users and adds about 15-16 million users a month, could witness robust growth in the sector given the fact that the economic downturn is showing signs of moderation.He said, the government intends to start the mobile number portability service early next year.The service will give more choice to customers who would be able to change their operator while retaining their cellular phone number. It will also encourage telecom companies to improve the quality of their service. Dr Singh said, the government has decided to implement a massive programme of broadband for all, under which all the 2.5 lakh gram panchayats in the country will be provided high speed broadband connectivity by 2012.The Prime Minister, however, expressed concern over the slow growth in telecom manufacturing in India.