May 2007: A Raja takes over as telecom minister.

August 2007: Process of allotment of 2G spectrum for telecom along with Universal Access Service (UAS) Licences initiated by the Department of Telecommunications (DoT).

September 25, 2007: Telecom ministry issues press note fixing October 1, 2007 as deadline for receiving application for UASL licences.

October 1, 2007: DoT receives 575 applications for UAS licences of 46 companies.

November 2, 2007: The Prime Minister writes to Raja directing him to ensure fair allotment of the 2G spectrum.

November 22, 2007: Finance Ministry writes to DoT raising concerns over the procedure adopted by it. Demand for review rejected.

January 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 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.

May 4, 2009: An NGO Telecom Watchdog files complaint to the Central Vigilance Commission (CVC) on the illegalities in the spectrum allocation to Loop Telecom.

May 19, 2009 : Another complaint filed to the CVC by one Arun Agarwal, highlighting grant of spectrum to Swan Telecom at throwaway prices.

2009: CVC directs CBI to investigate the irregularities in allocation of the 2G spectrum.

July 1, 2009: Delhi High Court holds advancing of cut-off date as illegal on a petition by telecom company S-Tel.

October 21, 2009: CBI registers an FIR against "unknown officers of DoT and unknown private persons/ companies under various provisions of IPC and Prevention of Corruption Act.

October 22, 2009: CBI raids DoT offices.

March 31, 2010: CAG says there were large scale irregularities in the spectrum allocation.

May, 2010: NGO Centre for Public Interest litigation moves Delhi High Court seeking probe into the scam by CBI.

May 25, 2010: Delhi HC dismisses the petition.

August 2010: Appeal filed in the SC against the HC order.

August 18, 2010: HC refuses to direct the Prime Minister to decide on a complaint by Janata Party chief Swamy seeking sanction to prosecute Raja for his involvement in the 2G scam.

September 24, 2010: Swamy moves SC seeking direction to the PM to sanction prosecution of Raja.

November 10, 2010: CAG submits report on 2G spectrum to government stating loss of Rs 1.76 lakh crore to exchequer.

November 14, 2010: Raja resigns as Telecom Minister

December 1, 2010: SC directs original tapes containing conversation between corporate lobbyist Niira Radia and others be handed over to it.

December 1, 2010: Raja questions CAG findings in the SC.

December 2, 2010: SC comes down heavily on Raja for bypassing and overruling PM's advice to defer allocation of 2G spectrum by a few days.

December 8, 2010: SC asks Centre to consider setting up of a special court to try 2G spectrum scam case.

December 8, 2010: ED submits report. Says money trail covers 10 countries, including Mauritius.

December 15, 2010: Swamy mentions in complaint that Raja favoured "ineligible" private companies Swan Telecom Pvt Ltd and Unitech Wireless Ltd in allocating the spectrum.

January 4, 2011: Swamy moves SC seeking cancellation of 2G spectrum licences.

Febuary 2, 2011: Raja, former Telecom Secretary Siddartha Behura and Raja's former Personal Secretary RK Chandolia arrested.

Febuary 8, 2011: Shahid Usman Balwa, promoter of Swan Telecom, arrested by CBI.

February 10, 2011: SC asks the CBI to bring under its scanner corporate houses which were beneficiaries of the 2G spectrum.

February 17, 2011: Raja sent to Tihar Jail under judicial custody.

February 18, 2011: Balwa sent to Judicial custody.

February 24, 2011: CBI tells Delhi Court Balwa facilitated transaction to Kalaignar TV.

February 28, 2011: Raja seeks judicial proceedings through video conferencing stating that he faces threat to life from fellow prisoners.

March 14, 2011: The Delhi High Court sets up special court to deal exclusively with 2G cases. Balwa also allowed to appear via video conferencing.

March 29, 2011: SC permits CBI to file charge sheet on April 2 instead of March 31. Two more persons - Asif Balwa and Rajeev Agarwal arrested.

April 2, 2011: The CBI files its first charge sheet in the 2G spectrum allocation scam.

April 25, 2011: CBI files second charge sheet and court issues summons to Kanimozhi, Sharad Kumar and Karim Morani taking cognisance of the charge sheet.

May 20, 2011: Court rejects bail pleas of Kanimozhi and Sharad Kumar and orders their forthwith arrest.

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

August 23, 11: Swamy moves SC for making Chidambaram an accused.

September 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.

September 15, 11: Swamy moves Special CBI court to make Chidambaram a co-accused.

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

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

October 22, 11: Special court frames charges against Raja and 16 others in the 2G case.

November, 11: Barring Raja and Behura, 12 others get bail.

December 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.

January 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.

February 2, 2012: SC cancels 122 licences granted during Raja's tenure. Directs auctioning of licences in 4 months.

May 9, 2012: SC grants bail to Siddharth Behura, upholds bail of RK Chandolia. A Raja too moves court for bail.

May 11, 2012: Behura walks out of Tihar jail.

May 15, 2012: Special CBI court grants bail to former Telecom Minister A Raja.