when did he become the prime minister?
In 2014
Introduction
Narendra Damodardas Modi ( ; born 17 September 1950) is an Indian politician serving as the 14th and current Prime Minister of India since 2014. 
full name of current prime minister of india Narendra Damodardas Modi
26 May 2014 2014 26 May 2014
Narendra Modi Narendra Modi Narendra Modi
Prime Minister Introduction Prime Minister
Narendra Modi was sworn in as the Prime Minister of India on 26 May 2014.  Narendra Damodardas Modi ( ; born 17 September 1950) is an Indian politician serving as the 14th and current Prime Minister of India since 2014. After the Bharatiya Janata Party led National Democratic Alliance won a landslide in the 2014 Lok Sabha election, Narendra Modi was sworn in as the Prime Minister of India on 26 May 2014.
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Narendra Modi [SEP] Introduction
Narendra Damodardas Modi ( ; born 17 September 1950) is an Indian politician serving as the 14th and current Prime Minister of India since 2014. He was the Chief Minister of Gujarat from 2001 to 2014 and is the Member of Parliament for Varanasi. Modi is a member of the Bharatiya Janata Party (BJP) and of the Rashtriya Swayamsevak Sangh (RSS), a Hindu nationalist volunteer organisation. He is the first prime minister outside of the Indian National Congress to win two consecutive terms with a full majority and the second to complete more than five years in office after Atal Bihari Vajpayee.