'Basu is suffering from 'gastro-intestinal distension' and also had a transient loss of consciousness Sunday morning. His blood pressure was also fluctuating earlier, but now it is normal,' Sharma had said Sunday.

A series of tests, including ECG, ultrasound, x-ray and blood examination, has been conducted on the Communist Party of India-Marxist (CPI-M) leader. 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.

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

Born 1914 in Kolkata, Basu became chief minister in 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 the United Front government. But the CPI-M vetoed the proposal, forcing him to dub the party's decision as a 'historical blunder'.