Ramadoss met CM Vijay at the Secretariat and handed over a letter, a copy of which was later released to the media.

In a letter addressed to Vijay, he said, "Tamil Nadu alone has gone beyond the usual 50 per cent cap and has implemented a 69 per cent reservation, and it is the only state that sought to include this ceiling in the Ninth Schedule of the Constitution. However, the reservation is now under threat."

He pointed out that in the case challenging the 69 per cent reservation, the Supreme Court’s judgment dated 13 July 2010 upheld it and at the same time directed that a caste-based census be conducted within a year to determine the exact extent of reservation.

Stating that reservation was confirmed without conducting the caste census, some parties again filed cases in 2012 against the 69 per cent limit. "When these cases came up for hearing on 27 May this year, although the Supreme Court dismissed certain connected petitions on the ground that some student petitioners had completed their studies, two principal cases remain pending".

"Those cases can be listed for hearing in the Supreme Court at any time," he said, adding, "If Tamil Nadu cannot demonstrate through a caste census that the population proportion of reserved communities justifies a 69 per cent reservation, there is a real risk that the 69 per cent ceiling may be struck down and therefore, it is necessary to conduct a caste-based enumeration in Tamil Nadu—commonly called a Social Justice Survey—to protect the 69 per cent reservation," the former union minister said.