Basu injured his left leg after another fall at his home May 13. This prevented him from casting his vote in the Lok Sabha polls two months back -- the first time in 63 years that he did not vote.

He had cracked a rib after a fall in the bathroom in 2007.

Born 1914 in Kolkata, Basu became chief minister in June 1977. He stepped down voluntarily on health grounds in November 2000.

One of the founding members of the CPI-M, Basu almost became India's prime minister in 1996 as the head of a coalition government. But the CPI-M vetoed the proposal.