Mobile tariffs in India, already among the lowest in the world, can fall by as much as 50% when new players start operations after getting spectrum, according to the Deparment of Telecom (DoT).According to an internal note prepared by DoT, mobile tariffs could fall by over 50% to about 40 paise per minute assuming four new players enter the fray and with the implementation of new norms such as usage of dual technology, number portability and allocation of spectrum to new players.At present, there are only three pan-India operators - Bharti Airtel, Reliance Communication and Bharat Sanchar Nigam, while Vodafone-Essar and Idea Cellular are waiting for additional spectrum to start services in some circles.At least 13 companies have applied for pan-India licences including AT&T, HFCL, Bycell, Parsavnath Developers, DLF and Shyam Telecom.On the issue of spectrum availability to accomodate new players, a DoT official said: "There is enough scope for allotment of spectrum to a few new operators even after meeting the requirements of existing operators and licensees."The government is processing the 575 applications and may issue letters of intent (LoIs) soon. With the increase in competition tariffs are bound to fall in all segments of services, be it local calls, roaming, national long distance or One-India call, DoT officials said.Asked by when LoIs would be issued to new applicants, officials said, "the process is on... Each applicant has submitted volumnous documents... A final decision will be taken soon."