NEW DELHI >> India’s former Prime Minister Manmohan Singh, widely regarded as the architect of India’s economic reform program and a landmark nuclear deal with the United States, has died. He was 92.

Singh was admitted to New Delhi’s All India Institute of Medical Sciences late Thursday after his health deteriorated due to a “sudden loss of consciousness at home,” the hospital said in a statement.

“Resuscitative measures were started immediately at home. He was brought to the Medical Emergency” at 8:06 p.m., the hospital said, but “despite all efforts, he could not be revived and was declared dead at 9:51 PM.”

Singh was being treated for “age-related medical conditions,” the statement said.

A mild-mannered technocrat, Singh became one of India’s longest-serving prime ministers for 10 years and leader of the Congress Party in the Parliament’s Upper House, earning a reputation as a man of great personal integrity. He was chosen to fill the role in 2004 by Sonia Gandhi, the widow of assassinated Prime Minister Rajiv Gandhi.

But his sterling image was tainted by allegations of corruption against his ministers.

Singh was reelected in 2009, but his second term as prime minister was clouded by financial scandals and corruption charges over the organization of the 2010 Commonwealth Games. This led to the Congress Party’s crushing defeat in the 2014 national election by the Hindu nationalist Bharatiya Janata Party under the leadership of Narendra Modi.

Singh adopted a low profile after relinquishing the post of prime minister.

Prime Minister Modi, who succeeded Singh in 2014, called him one of India’s “most distinguished leaders” who rose from humble origins and left “a strong imprint on our economic policy over the years.”

“As our Prime Minister, he made extensive efforts to improve people’s lives,” Modi said in a post on social platform X. He called Singh’s interventions in Parliament as a lawmaker “insightful” and said “his wisdom and humility were always visible.”

Rahul Gandhi, from the same party as Singh and the opposition leader in the lower house of the Indian Parliament, said Singh’s “deep understanding of economics inspired the nation” and that he “led India with immense wisdom and integrity.”

“I have lost a mentor and guide. Millions of us who admired him will remember him with the utmost pride,” Gandhi wrote on X.

Born on Sept. 26, 1932, in a village in the Punjab province of undivided India, Singh’s brilliant academic career took him to Cambridge University in Britain, where he earned a degree in economics in 1957. He then got his doctorate in economics from Nuffield College at Oxford University in 1962.

Singh taught at Panjab University and the prestigious Delhi School of Economics before joining the Indian government in 1971 as economic advisor in the Commerce Ministry. In 1982, he became chief economic adviser to the Finance Ministry. He also served as deputy chair of the Planning Commission and governor of the Reserve Bank of India.

Singh is survived by his wife Gursharan Kaur and three daughters.