Prime Minister Narendra Modi greeted his predecessor Manmohan Singh on his 90th birthday on Monday.
Singh, a renowned economist, was India's prime minister between 2004-14 during the Congress-led UPA rule.
He was also India's finance minister in the P V Narasimha Rao-led government during 1991-96, an epochal era for the country's economy marked by wide-ranging reforms.
Modi tweeted, "Birthday greetings to former PM Dr. Manmohan Singh Ji. Praying for his long and healthy life."