India’s longest serving CM was Jyoti Basu, who was the Chief Minister of West Bengal from 21 June 1977–26 October 2000. He held the post for a record five terms, and was a member of the Communist Party of India (Marxist). As of 2017 however, Pawan Chamling, the fifth and incumbent Chief Minister of Sikkim seems poised to break Jyoti Basu’s record.