First, The Statesman has a good article recounting the history of reservation in Tamil Nadu:
The first standing order on reservation (No 128-2) was passed in the Madras Presidency by the British government in 1854. The collectors were told to divide the subordinate appointments in their districts among the principal castes. Madras Presidency comprised the whole of Tamil Nadu and Andhra Pradesh, parts of Kerala and Karnataka and a small portion of Orissa. The order was soon mired in protests by the then babudom and was not implemented.
The South Indian Liberal Federation (SILF), popularly known as the Justice Party ~ after the English daily it published called Justice) ~ which came to power towards the end of 1920, passed a new order (GO No 613) in 1921, reserving government jobs for various caste-based social classes. [...]
Next, the Hindu reports on the legal case against Tamil Nadu's 69 percent quota-regime which violates the Supreme Court-mandated upper limit of 50 percent.
The Supreme Court will go into the constitutional validity of the Tamil Nadu Reservation Act providing for 69 per cent quota in educational institutions and employment.
A nine-judge Constitution Bench will also examine the validity of the subsequent law enacted by Parliament to include the Act under the Ninth Schedule for taking away the court's power of judicial review. The Bench will hear a batch of petitions questioning Parliament's powers to enact laws and include them in the Ninth Schedule. It will examine whether an earlier five-judge Bench decision "that all Constitution amendments by which additions were made to the Ninth Schedule on or after April 24, 1973 [when judgment in the Kesavanand Bharti case was delivered] will be valid only if they do not damage or destroy the basic structure of the Constitution" is correct or not.