He was 92 and is survived by his wife, two sons and three daughters. His eldest son had predeceased him.
Sinha was suffering from fever and was admitted to the Gauhati Medical College Hospital yesterday. After his condition deteriorated last night, he was shifted to the intensive care unit where he breathed his last this morning.
A colossus in Assam's political arena, Sinha was the Congress Chief Minister during emergency. Meghalaya was carved out of Assam, whose capital was shifted to Guwahati from Shillong, during his tenure.
Born on January 1, 1914 to a poor farmer's family in Bhakatpara village of Dhubri district, Sinha received his early education in the village school.
After completing his middle level education, he joined High School in Bilasipara, about 25 kms away, a distance he covered daily on foot.
He completed his graduation from Cotton College in Guwahati and went to study law and post-graduation in Benares Hindu University.
After receiving his law degree, Sinha returned to Guwahati to practise for a brief period but soon left for Dhubri to become a teacher and later became the headmaster of several schools in the district.
Sinha entered politics in 1946 and served in different capacities in Congress, including its General Secretary, Vice-President and President. He was elected to the state assembly four times from Bilasipara constituency and served as Chief Minister for six years from 1972 to 1978.
Considered close to Indira Gandhi during the pre-emergency era, Sinha was made the interim Chief Minister in 1972 and assembly elections followed soon and he became the elected Chief Minister.
Sinha was, however, disillusioned by the emergency and became a member of Congress(S) after the party split to form Congress(I).
He joined NCP when his close friend Sharad Pawar left the Congress to form the new party.
Sinha was relcutant to hold any party post due to advancing age but was later appointed its president though he stepped down last week to pave way for younger members.
Besides the emergency and transfer of Assam's capital to Guwahati, the other major issues that rocked the state during his tenure was the language agitation demanding the introduction of Assamese as the sole of medium of instruction.
He was also a great champion of the coooperative and Panchayati Raj movements and strived hard to bring reforms in these sectors.