Arvind Panagariya resigned as vice chairman of the Niti Aayog today, saying he would like to return to academics in the US. The 64-year-old economist said he had written to Prime Minister Narendra Modi to relieve him of his duties by August 31 as he was not getting an extension of leave from the Columbia University. He said he had discussed his exit two months ago with PM Modi, who is the chairman of Niti Aayog.