"We cannot allow Calcutta High Court order to operate," a Bench headed by Chief Justice K G Balakrishnan said.

"Can Calcutta High Court sit over the order of the Supreme Court," the Bench asked while vacating the stay.

The Bench said that when the apex court had upheld the validity of the act providing the OBC quota, where was the question of High Court staying its implementation.

However, the court said, subject to the final outcome of the matter before it, all admissions will be provisional in post graduate courses in Central educational institutions under the Act.

The Court stayed all proceedings relating to OBC quota that are pending in the High Courts of Delhi, Calcutta and Bombay.