The Bench had reserved its verdict on April 19 lat year on a petition filed by the family of Devinderpal Singh Bhullar, the Khalistan Liberation Force terrorist.
Bhullar was awarded death penalty for his role in the bomb attack on former Youth Congress president M S Bitta in 1993. Nine policemen were killed while 25, including Bitta, were injured.
Bhullar had pleaded for commutation of the death sentence, saying he had already served jail term for 20 years, which was akin to life term and also claimed to have lost mental equilibrium during an agonising 11-year wait.
A bench comprising Justices G S Singhvi and S J Mukhopadhaya had heard the arguments of the three petitions - one by Bhullar, second by his wife Navneet Kaur and another by NGO 'Justice on Trial Trust', in details.
Bhullar's counsel said the fear of execution at any moment for such a long period took a toll on Bhullar's mind and made the case fit for commutation of the capital sentence into life term.
The apex court's verdict is likely to have an influence on many others' pleas, including those of convicts in the assassination of former prime minister Rajiv Gandhi and four aides of slain sandalwood smuggler Veerappan.