Mr Javadekar told reporters that it was the Prime Minister who called him in Germany, where he was attending a climate change conference.
“I was abroad when Prime Minister called up and told me about it. He asked me to reach Delhi immediately,” Mr Javadekar told reporters at Rashtrapati Bhavan or the presidential palace, where he was the first of 19 ministers to take oath today.
Five ministers have been dropped by Prime Minister Modi. His council of ministers now adds up to 78.
Mr Javadekar, who for two years headed the Environment Ministry, was originally also Junior Minister for Information and Broadcasting and Parliamentary Affairs, but lost those two portfolios in November 2014.
Mr Javadekar, a former banker, represents Madhya Pradesh in the Rajya Sabha. He was not a member of parliament when Prime Minister Modi formed his government.
The 65-year-old politician is a commerce graduate, and won props within his party for being an effective spokesperson when the BJP was the main opposition party.
Placed in charge of Andhra Pradesh, he is credited with bringing the ruling party in the state – Chandrababu Naidu’s TDP, into the national coalition headed by the BJP ahead of the general election in 2014.