The nonagenarian leader underwent a brain scan Monday. It showed that a clot caused by a fall last year at his home was gradually healing.

Doctors had then advised Basu, who was chief minister for 23 long years until 2000, to undergo surgery but he decided against it.

He 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.

In 2007, after a fall in the bathroom, one of his ribs had also cracked.

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.