Following is the chronology of events in the case involving constitutional validity of the controversial law providing 27 per cent quote for Other Backward Classes in Central Educational Institutions, including IITs and IIMs:

• January 20, 2006: The Constitution (93rd amendment) Act, 2005 comes into effect empowering the state to make special provisions for socially and educationally backward classes and SC/STs in admission to educational institutions.
• May 16, 2006: The Standing Committee on social justice and empowerment submits its 15th report stating that there was no census in the case of backward classes. It mentions that a report of Registrar General of India that no information has been collected on OBCs in 2001 census.
• May 22, 2006: Ashok Kumar Thakur files a petition in the Supreme Court challenging the Central Educational Institutions (Reservation in Admission) Act, 2006, when anti-quota agitation at AIIMS was at its peak.
• May 27, 2006: Prime Minister Manmohan Singh constitutes an Oversight Committee to look into the implementation of 27 per cent reservation for the OBCs in higher educational institutes. The Committee, in its report, cautions the government that the implementation of the Act would compromise academic excellence and lead to 'demographic disaster'.
• May 29, 2006: The Supreme Court issues notice to the Centre on the petition.
• May 31, 2006: The Supreme Court permits all concerned citizens to be impleaded as parties in the on-going petition and allows them to file a fresh petition.
• December 1, 2006: A Parliamentary Standing Committee on human resource and development submits its 186th report in both houses of Parliament saying no caste-based census has been carried out after 1931.
• January 1, 2007: Another petition challenging the implementation of the Act is filed in the Supreme Court.
• Mar 29, 2007: The Supreme Court gives interim order staying the implementation of the Act.
• August 7, 2007: The five-judge Constitution bench commences hearing to decide the validity of the Act.
• November 11, 2007: After 25 days of hearing, judgment in the matter was reserved.
• April 10, 2008: The Supreme Court upholds the validity of the Central Educational Institutions (Reservation in Admission) Act, 2006 providing 27 per cent quota to OBCs in the educational institutions.