‘‘What is the hurry in bringing the legislation in the absence of relevant determination of socially and economically backward classes?... We cannot go further unless we are satisfied that there is determination of socially and economically backward classes,’’ said a Bench comprising Justices Arijit Pasayat and L S Panta.

‘‘Unless and until it is determined by the Centre who is socially and economically backward, this Act cannot really be given effect,’’ the Bench said as the anti-quota petitioners opposed implementation of the law on the ground that a 75-year-old census could not be the basis for identifying OBCs.

While submitting its response to the petitions, the Government had informed the court that it was relying on a 1931 census to provide 27 per cent reservation for OBCs in institutions like IIMs and IITs.

Objecting to this census as the basis for identification of backward classes, senior counsel Fali S Nariman argued that until the identification process is done, reservation should not be implemented. ‘‘The said Act is silent on the methodology as to how the government proposes to do it,’’ he said.

But Additional Solicitor General Gopal Subramanium maintained that implementing the statute would not affect rights of the general category candidates. ‘‘The best part of the Act is that it ensures the rights of the general category students.’’

But the Bench sought to know the urgency behind the Act. ‘‘You wait for two years There should not be urgency. If this Act was enacted after complete study, there would not be any difficulty in going ahead with it,’’ the Bench said, asking the ASG, ‘‘Don’t you think that the 1931 data has lost its efficacy’’.

Nariman, who made it clear that he was not seeking setting aside of the Act but merely deferment of implementation of the Act, said that it did not lay down the criteria on the basis of which the Centre will determine the socially and economically backward class. It was also not necessary that a upper caste person was economically well-off and a socially backward person educationally backward, he said.

“Without proper methodology for determination of OBCs, we cannot go ahead with admissions for 2007,” he said.

According to Nariman, the Act was also silent on excluding the “creamy layer” among backward castes from the benefit of reservation. “Who forms the creamy layer has been well settled by a set of judgments,” he said, adding that “ex-facie there has been no exclusion of creamy layer from the benefit of reservation in the Act.”