NEW DELHI (AP) — 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 “sudden loss of consciousness at home,” the hospital said in a statement. He was “being treated for age-related medical conditions,” the statement added.

A mild-mannered technocrat, Singh became one of India’s longest-serving prime ministers for 10 years and earned 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 elected to a second term as prime minister from 2009-2014 that 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.