NEW DELHI: India's top court on Tuesday rejected a final appeal by Yakub Memon, a key plotter of bomb attacks that killed hundreds in Mumbai in 1993, paving the way for his execution.

Media reports said Yakub Memon would hang on July 30 — more than two decades after the deadliest attacks ever to hit India —after the Supreme Court rejected his final plea.

The Bombay Stock Exchange, the offices of Air India and a luxury hotel were among the targets of the March 1993 blasts, which killed 257 people in India's commercial capital.

The attacks were believed to have been staged by Mumbai's Muslim-dominated underworld in retaliation for anti-Muslim violence that had killed more than 1,000 people.

Memon was the only one of 11 people convicted for the 1993 attacks to have his death sentence upheld on appeal. The sentences on the others were commuted to life imprisonment.

Executions are only carried out for “the rarest of rare” cases in India.

But President Pranab Mukherjee has rejected a number of mercy pleas in recent years, ending an unofficial eight-year moratorium.

A Kashmiri separatist convicted of involvement in a deadly 2001 attack on the Indian parliament was executed in New Delhi in 2013, while the lone surviving gunman from the deadly 2008 Mumbai attacks was hanged in 2012.

“Crimes such as these deserve maximum punishment,” Meenakshi Ganguly, South Asia director for Human Rights Watch, told AFP.

“But we believe that the maximum punishment should not be the death penalty because it is inherently inhumane,” she said.

Mastermind on the run

Amnesty India said it was disappointed by the Supreme Court's decision in the case.

“The judgement regrettably puts India in opposition to the global trend towards moving away from the death penalty,” the rights group said.

“There exists no reliable evidence that the threat of execution is more of a deterrent to crime than a prison sentence,” it said on Twitter.

Memon, an accountant by profession, denied any involvement in the blasts during a staggered trial and appeal process.

He and two of his brothers, Essa and Yusuf Memon, were convicted in 2006 under Indian anti-terrorism laws of conspiracy and abetting the attacks.

Another brother Tiger Memon was alleged to have masterminded the attacks along with Mumbai gang boss Dawood Ibrahim. Both have been on the run since 1993.

The Memons left for Dubai in the days before the bombs exploded but were arrested when they returned to India in 1994.

Eight members of the family were charged over the attacks but Memon's father died during the long-running legal proceedings, and three others were acquitted. They had all denied any role in the attacks.

The bombings also embroiled Bollywood star Sanjay Dutt, who is serving a prison sentence for buying weapons from gangsters accused of orchestrating the bombings.

Memon was convicted by a specially designated court under the draconian Terrorist and Disruptive Activities (Prevention) Act, which was promulgated immediately after the 1993 bomb blasts.

However the Act lapsed two years later and was never revived, with activists accusing the government of using it to harass Muslims.