"The last 12 years at IndiGo has been the most satisfying and rewarding experience of my career. I am extremely proud to have been a part of commercial success of the airline," said Mr Kumar.
Mr Kumar, who has over 20 years of experience in the aviation sector, has worked with Sahara Airlines, Royal Airways Limited. He joined IndiGo on January 29, 2007, according to IndiGo's website.
Rahul Bhatia, interim CEO of IndiGo, said: "I would like to thank Sanjay for all he has done for the Company in making IndiGo the airline it is... I am grateful for all his hard work since he joined in January 2007 and wish him all the best in his future endeavours."
Founded in 2006 by travel entrepreneur Rahul Bhatia and Rakesh Gangwal, a former chief executive of US Airways, IndiGo has grown rapidly to become the country's largest airline.