A bench headed by Justice G S Singhvi asked the Centre to file an affidavit by October 10, explaining the delay in deciding Bhullar's mercy plea of 2003, rejected by President in 2011.
"Everybody is anxious to know what happened during these eight years. What happened between 2003 and 2011?" the court said while asking the government to file its response.
Bhullar was sentenced to death by a TADA court on August 25, 2001 for his role in the September 10, 1993 bomb blast in Delhi targeting the cavalcade of then Youth Congress President Maninderjit Singh Bitta who escaped with serious injuries, though nine security personnel were killed.
The Supreme Court had on March 26, 2002 dismissed Bhullar's appeal against the death sentence.
He had then filed a review petition which was also dismissed on December 17, 2002. Bhullar then moved a curative petition which too was dismissed by the apex court on March 12, 2003. Bhullar, meanwhile, had filed a mercy petition before the President on January 14, 2003.
The President, after a lapse of over eight years, dismissed his mercy plea on May 25 this year.