premise: Mamata Banerjee is an Indian politician.
hypothesis: Mamata Banerjee ( [ mɔmɔt̪a bɔnd̪d̪oˈpad̪ʱˈae̯ ] ( Bengali - মমতা বন্দপাধ্যায় ) also known as Didi was born 5 January 1955 ) is an Indian politician who has been Chief Minister of West Bengal since 2011 . Banerjee founded the party All India Trinamool Congress ( AITMC or TMC ) in 1997 and became its chairperson , after separating from the Indian National Congress . Banerjee previously served as the Minister of Railways twice and is also the first woman Railway Minister of India , Minister of Coal , and Minister of State for Human Resource Development , Department of Youth Affairs and Sports and Women and Child Development in the cabinet of the Indian government . In 2011 Banerjee pulled off a landslide victory for the TMC Congress alliance in West Bengal , defeating the 34-year-old Communist Party of India ( Marxist ) - led Left Front government , the world 's longest-serving democratically elected communist government in the process . The TMC leader was voted in May 2013 as India 's most honest politician in an internal poll by members of India Against Corruption , India 's largest anti-corruption coalition .