In an apparent setback to the campaign for those seeking stringent punishment for the accused in the Bhopal gas disaster, the Supreme Court on Wednesday dismissed CBI's curative petition against an earlier apex court judgement that diluted charges against the accused.

A five-judge constitutional bench, headed by Chief Justice S.H. Kapadia, however, left a window of opportunity open saying the pending proceedings before the sessions court against the chief judicial magistrate's judgement awarding two years sentence to the accused, including Union carbide india chairman Keshub Mahindra will not be influenced by any order passed by it.

The bench said that the CBI and the MP government have failed to come out with a satisfactory explanation on filing the curative petition after a lapse of 14 years.

The unanimous order was passed by the bench that included justices Altamas Kabir, R.V. Raveendran, B. Sudershan Reddy and Aftab Alam.

The CBI and the Madhya Pradesh government filed the curative petitions after a public outcry over what was considered as a mild punishment for a tragedy that claimed over 15,000 lives in December 1984 and had left several thousands maimed by the leakage of deadly Methyl Isocyanate gas.

In 1996, a two-judge bench of the apex court, headed by the then Chief Justice A.H. Ahmadi had diluted the charges against the accused from Section 304 Part II of the IPC providing for a maximum of ten years imprisonment to Section 304(A) that deals with rash and negligence act with a maximum punishment of two years.

The CBI and the MP government have filed revision petitions in the sessions court against the judgement of the CJM, Bhopal, which had awarded two years jail term to various accused in the Bhopal gas tragedy case.

The CBI had sought recall of the apex court's14-year-old judgement that had diluted the charges against the accused, who were prosecuted just for the offence of being negligent.

In its plea, the CBI had sought restoration of stringent charge of culpable homicide not amounting to murder instead of death caused due to negligence against the accused in the world's worst industrial disaster.

Madhya Pradesh government had also moved the apex court, endorsing the CBI plea for review of the September 1996 judgement by which the accused persons were tried for the offence of criminal negligence which resulted in a lighter punishment of two years' jail term to Mahindra and six others on June 7, 2010.

The others who escaped with lighter punishment included UCIL erstwhile managing director Vijay Gokhale, its vice-president Kishore Kamdar, works manager J.N. Mukund, production manager S.P. Choudhary, plant superintendent K.V. Shetty and production assistant S.I. Quereshi.

The apex court had on August 31 last decided to re-examine its own judgement that led to lighter punishment of two years imprisonment for all the seven convicts.

The verdict had sparked a nationwide outrage following which the government set up a group of ministers and filed a curative petition against the lighter punishment for those responsible for the gas tragedy.

Earlier, Attorney General Goolam E. Vahanvati, appearing for the CBI, had pleaded the court to review its 1996 judgement saying that the investigating agency's decision to file the curative petition was taken on the facts "which shook our conscience".

Requesting the apex court to modify its earlier order, he had said, "It is our duty to do justice and it should prevail in public interest".

"Lots of values are involved in it and it was one of the rarest situation," he had pleaded.

Senior advocate Ram Jethmlani, appearing for 81-year-old professor Ramaswamy R Iyer who had intervened in the case, had, however, accused CBI of "shedding crocodile tears" and pleaded with the court to ask the government to reveal information on how it negotiated with the Union carbide on the compensation for victims.

He had further said politicians and bureaucrats have messed up the entire issue.