While DMK supporters and Congress leaders hailed the court's decision, the BJP appeared standoffish over the verdict, which came after a six-year-long trial. Following is the chronology of events on what is believed to be India's biggest scam.
October 21, 2009: CBI registers case related to alleged irregularities in allocation of 2G Spectrum.
May 2010: NGO Centre for Public Interest litigation or CPIL moves Delhi High Court seeking Central Bureau of Investigation or CBI probe into irregularities in spectrum allocation.
October 8, 2010: Supreme Court seeks government's response on Comptroller and Auditor General's or CAG report on the alleged scam. Vinod Rai was the CAG during the time.
November 10, 2010: CAG pegs loss to exchequer at Rs.1.76 lakh crore.
November 14, 2010: A Raja resigns as the communications and information technology minister.
December 8, 2010: Supreme Court orders setting up of a special court to look into 2G scam.
February 2, 2011: Mr Raja gets arrested.
April 2, 2011: CBI files chargesheet in the case.
April 29, 2011: CBI files supplementary chargesheet in the case.
September 15, 2011: BJP leader Subramanian Swamy goes to CBI special court seeking P Chidambaram to be made co-accused.
October 22, 2011: Special CBI court frames charges against 17 accused, including Mr Raja.
October 22, 2011: Court frames charges against Mr Raja and others.
November 11, 2011: Trial begins in the case.
December 12, 2011: CBI submits third charge sheet, including names of Essar promoters Anshuman Ruia, Ravi Ruia, Essar Group director strategy and planning Vikas Saraf, Loop Telecom promoters Kiran Khaitan and her husband IP Khaitan as accused. Loop Telecom Pvt Ltd, Loop Mobile India Ltd and Essar Tele Holding also recognised as accused.
February 2, 2012: The Supreme Court orders cancellation of 122 licences issued in 2008, gives companies four months to cease operations.
February 4, 2012: Trial court dismisses Mr Swamy's plea to make Home Minister P Chidambaram an accused.
November 28, 2011: DMK MP Kanimozhi gets bail.
May 15, 2012: Mr Raja gets bail.
May 25, 2012: Court frames charges against promoters of Essar and Loop, grants bail.
April 25, 2014: ED chargesheets Mr Raja, Ms Kanimozhi and others.
October 31, 2014: Money laundering charges framed against Mr Raja, Ms Kanimozhi and others.
November 17, 2014: Trial begins in money laundering case.
December 5, 2017: Court sets December 21 as judgement day in the case.
December 21: All including Mr Raja, Ms Kanimozhi acquitted in the case. "Justice has prevailed," says Ms Kanimozhi.
(With inputs from IANS)