Chaudhary Charan Singh (1902–1987) 5th Prime Minister of India

28 July 1979 – 14 January 1980 (170 days), making him the shortest-tenured Prime Minister in India’s history.

Chaudhary Charan Singh was a prominent leader of the Lok Dal party and was known for his advocacy for farmers and rural areas.

He became Prime Minister after the resignation of Morarji Desai in 1979, following a period of political instability.

His tenure was marked by instability, primarily because his coalition government lacked broad support from key political parties, including the Congress party. His administration was unable to secure sufficient backing in the Parliament.

Faced with the lack of support, Charan Singh’s government collapsed, and he resigned on 14 January 1980, leading to the general elections in which Indira Gandhi and the Indian National Congress returned to power.

Gulzari Lal Nanda (1898–1998) Acting Prime Minister of India

27 May 1964 – 9 June 1964 (after Jawaharlal Nehru’s death)

11 January 1966 – 24 January 1966 (after Lal Bahadur Shastri’s death)

Gulzari Lal Nanda served as Acting Prime Minister on two occasions:

First tenure (1964): He took over after the death of Jawaharlal Nehru on 27 May 1964, until Lal Bahadur Shastri was elected Prime Minister.

Second tenure (1966): He assumed the role again after the death of Lal Bahadur Shastri on 11 January 1966, until the election of Indira Gandhi as Prime Minister.

Gulzari Lal Nanda’s acting tenures were indeed shorter than Charan Singh’s full tenure as Prime Minister. Nanda served as Acting Prime Minister in brief intervals, whereas Charan Singh served a full term, though it was short-lived due to the political instability he faced.

Chaudhary Charan Singh’s tenure was the shortest for a Prime Minister, but Gulzari Lal Nanda holds the distinction of serving as Acting Prime Minister twice for even shorter periods.