The company's board has taken on record his resignation which will be affective from close of business hours on April 30, 2018, it said.
Sardana has over 3 decades of experience in the power and infrastructure sector. He had also worked at companies like NTPC Ltd and BSES.
He was the Managing Director of Tata Teleservices Ltd for over 3 years from 2007 to 2011. He is also on the board of other companies.