The 86-year-old Congress leader from Rajasthan had been suffering from various ailments for some time and was "chronically ill", sources in Medanta Medicity said. (Agencies)
The end came at 3:40 AM at the hospital.
Ola had undergone an eye surgery and an intestine operation at the hospital where he was admitted since November, his family said.
The Jat leader is survived by his wife, two sons and a daughter.
Ola will be cremated later in the evening in his native village in Jhunjhunu district of Rajasthan. Prime Minister Manmohan Singh has expressed grief at his demise.
The Union Cabinet, of which Ola was a member since June 17, this year, will meet at the Prime Minister’s residence to mourn his death.
Condoling his demise, Rajasthan Chief Minister Vasundhara Raje and former Chief Minister Ashok Gehlot said, "Ola's death has created a vacuum in state politics".
A recipient of the Padma Shri award in 1968, Ola started girls education in a remote area in rural Rajasthan with three girls in the school known as Indira Gandhi Balika Niketan Ardawata in 1952.
Born on 30 July, 1927, Ola represented the Jhunjhunu constituency of Rajasthan in the Lok Sabha and was a member of the Rajasthan Legislative Assembly from 1957 to 1990, and from 1980 to 1990 he was a cabinet minister in the Government of Rajasthan. Ola has been elected to the Lok Sabha five times and the Rajasthan assembly eight times.
He was Union Minister of State for Chemicals and Fertilizers (Independent Charge) from 1996 to 1997 and Union Minister of State for Water Resources (Independent Charge) from 1997 to 1998.
Ola was Union Cabinet Minister of Labour and Employment from May 23, 2004 to November 27, 2004 and was Union Cabinet Minister of Mines in the Manmohan Singh's government.
His son Bijender Ola is a MLA from Jhunjhunu and was a former minster in the Rajasthan government.
The 86-year-old Congress leader from Rajasthan had been suffering from various ailments for some time and was "chronically ill", sources in Medanta Medicity said.