Following is the chronology of events in the 2G scam case in which the Supreme Court on Thursday cancelled 122 licenses granted during the tenure of A. Raja as telecom minister:

*May 2007: Raja takes over as Telecom Minister.

*Aug 07: Process of allotment of 2G spectrum for telecom along with Universal Access Service (UAS) Licences initiated by the Department of Telecommunications (DoT).

*Sept 25, 07: Telecom Ministry issues press note fixing deadline for application as October 1, 2007.

*Oct 1, 07: DoT receives 575 applications for UAS licences of 46 companies.

*Nov 2, 07: PM writes to Raja directing him to ensure allotment of 2G spectrum in a fair and transparent manner and to ensure licence fee was properly revised. Raja writes back to PM rejecting many of his recommendations.

*Nov 22, 07: Finance Ministry writes to DoT raising concerns over the procedure adopted by it. Demand for review rejected.

*Jan 10, 2008: DoT decides to issue licences on first- come- first served basis, preponing the cut-off date to September 25, from October 1, 2007.

Later on the same day, DoT posted an announcement on its website saying those who apply between 3.30 pm and 4.30 pm would be issued licences in accordance with the said policy.

*2008: Swan Telecom, Unitech and Tata Teleservices sell off a part of their stakes at much higher rates to Etisalat, Telenor and DOCOMO respectively.

*Nov 29, 08: Subramanian Swamy makes representation to the PM, seeks sanction to prosecute Raja under the Prevention of Corruption Act.

*May 4, 2009: NGO Telecom Watchdog files complaint to CVC on illegalities in spectrum allocation to Loop Telecom.

*09: CVC directs CBI to probe allocation of 2G spectrum.

*July 1, 09: Delhi HC holds advancing of cut-off date as illegal on a petition of telecom company S-Tel.

*Oct 21, 09: CBI lodges FIR against unknown persons including DoT officials under the IPC and the Prevention of Corruption Act. *Oct 22, 09: CBI raids DoT offices.

*Nov 16, 09: CBI seeks details of tapped conversation of corporate lobbyist Niira Radia to find out involvement of middlemen in grant of spectrum to telecom companies.

*Mar 31, 10: CAG reports large scale irregularities.

*May 6, 2010: Telephonic conversation between Raja and Radia made public.

*May, 10: NGO Centre for Public Interest litigation moves Delhi HC seeking probe into scam either by SIT or CBI.

*May 25, 10: Delhi HC dismisses the petition.

*Aug 10: The NGO moves SC against HC's verdict.

*Aug 18, 10: Delhi HC refuses to direct PM to decide on Swamy's complaint seeking sanction to prosecute Raja for his involvement in 2G scam.

*Sept 13, 10: SC asks Centre, Raja to reply in 10 days to three petitions of CPIL and others on allegation there was a Rs 70,000 crore scam.

*Sept 24, 10: Swamy moves SC seeking direction to the PM to sanction Raja's prosecution.

*Oct 8, 10: SC asks government to respond to CAG report about the scam.

*Oct 21, 10: Draft reports of CAG placed before SC.

*Oct 29, 10: SC pulls up CBI for tardy probe in the scam.

*Nov 10, 10: CAG report says the scam caused a loss of Rs 1.76 lakh crore to exchequer.

*Nov 11, 10: DoT files affidavit in SC saying CAG did not have authority to question policy decision on 2G licenses.

*Nov 14, 10: Raja resigns as Telecom Minister.

*Swamy's plea on sanction to prosecute Raja becomes infructuous. He seeks guidelines on grant of sanction to prosecute public servants for offences under the Prevention of Corruption (PC) Act.

*Nov 20, 10: PM files affidavit in SC. Rejects charge of inaction on Swamy's complaint.

*Nov 22, 10: CBI tells SC that it will file charge sheet in the case within three months.

*Nov 22, 10: CBI tells SC that it will also examine the role of Radia.

*Nov 24, 10: SC reserves verdict on Swamy's plea seeking direction to PM for grant of sanction to prosecute Raja.

*Nov 25, 10: SC ticks off CBI for not questioning Raja. *Nov 29, 10: CBI files status report on probe in the case.

*Nov 30, 10: SC questions CVC P J Thomas's moral right to supervise CBI's probe into 2G spectrum scam as he himself was Telecom Secretary at that point of time.

*Dec 1, 10: SC seeks original tapes on conversation between corporate lobbyist Niira Radia and others.

*Dec 1, 10: Raja questions CAG findings in SC.

*Dec 2, 10: Government places recorded tapes in the SC.

*Dec 2, 10: SC comes down on Raja for overruling PM's advice to defer allocation of 2G spectrum by a few days.

*Dec 8, 10: SC favours probe into spectrum allocation since 2001.

*Dec 8, 10: SC orders setting up of a special court to try 2G spectrum scam case.

*Dec 8, 10: ED submits report. Says money trail covers 10 countries, including Mauritius.

*Dec 14, 10: Another PIL in SC for cancellation of telecom licences granted by Raja.

*Dec 15, 10: Swamy, in complaint, says Raja favoured 'ineligible' companies like Swan Telecom and Unitech.

*Jan 4, 11: Swamy also seeks cancellation of 2G licences.

*Jan 10, 11: SC notice to Centre on the plea seeking cancellation of 2G licences. It also seeks responses from 11 firms for not fulfilling roll-out obligations.

*Feb 2, 11: Raja, former Telecom Secretary Siddartha Behura and Raja's former Personal Secretary R. K. Chandolia arrested.

*Feb 8, 11: Shahid Usman Balwa, promoter of Swan Telecom, arrested.

*Feb 10, 11: SC asks CBI to probe corporate houses, alleged beneficiaries of the 2G scam.

*Mar 1, 11: CBI tells SC that 63 persons were under its scanner.

*Mar 14, 11: Delhi HC sets up special court for 2G case.

*Apr 2, 11: CBI files first charge sheet in the case.

*Apr 25, 11: CBI files second charge sheet and Kanimozhi, Sharad Kumar and Karim Morani summoned.

*May 20, 11: Court rejects bail pleas of Kanimozhi and others and orders their arrest.

*July 25, 11: Arguments on charge framing begins. Raja seeks to make PM and P. Chidambaram as witnesses.

*Aug 23, 11: Swamy moves SC for making Chidambaram as accused.

*Sept 8, 11: SC asks Swamy to submit his correspondences with CBI in connection with his plea to probe Chidambaram for his alleged role in the 2G scam.

*Sept 8, 11: SC agrees to hear CPIL's plea for setting up of a Special Investigating Team (SIT) to monitor probe.

*Sept 15, 11: Swamy moves Special CBI court to make Chidambaram a co-accused. *Sept 22, 11: CBI defends Chidambaram in SC, blames DoT.

*Sept 29, 11: CBI says role of Anil Ambani being probed, gives a clean chit to Tata and Videocon group.

*Oct 10, 11: SC reserves order on Swamy's plea for a probe into the alleged role of Chidambaram in the 2G scam.

*Oct 22, 11: Special court frames charges against Raja and 16 others in the 2 G case. *Nov, 11: Barring Raja and Behura, 12 others get bail.

*Dec 12, 11: CBI files third charge sheet. Names Essar promoters Anshuman, Ravi Ruia, Essar Group director (Strategy and Planning) Vikas Saraf, Loop Telecom promoters Kiran Khaitan and her husband I. P. Khaitan as accused.

Three companies-- Loop Telecom Pvt Ltd, Loop Mobile India Ltd and Essar Tele Holding also named as accused.

*Jan 31, 12: SC says filing complaint under the PC Act is a constitutional right and the competent authority should take a decision on giving the sanction within four months.

*Feb 2, 2012: SC cancels 122 licences granted during Raja's tenure. Directs auctioning of licences in 4 months. SC leaves it to the special court to decide on Chidambaram within 2 weeks.

Asks CBI to give status report on probe to CVC, making it a virtual SIT.