DoT sources said the company has applied for GSM spectrum for 22 circles under the unified access services licence.

DoT, last week, allowed cross-over technology under which an operator can offer both CDMA- and GSM-based mobile services with the same licence after paying the Rs1,660 crore entry fee of a UAS licence.

Rival CDMA operator Reliance Communications, which had applied for GSM spectrum last year, was given the letter of intent last week for starting pan-India GSM service. The Anil Ambani group firm has also paid the required fee.

RCoM was already offering GSM services under a different licence given to its sister concern Reliance Telecom. For Tatas, this would be a first-time entry into the GSM technology.

If granted necessary approvals, Tatas should get 4.4 MHz of initial spectrum to roll out GSM services.

The Tatas move to enter GSM mobile telephony, coming in the wake of Anil Ambani group company Reliance Communications (RCOM) getting government nod for the similar services, is likely to intensify the fight for scarce spectrum.

While RCOM deposited Rs1,651 crore within hours of the new guidelines for a nationwide spectrum, the Birla group led by Kumar Manglam Birla is understood to have sought prime minister''s intervention against the guidelines that celluar operators association considers are heavily tilted in favour of CDMA operators.