Niti Aayog vice-chairman Arvind Panagariya on Tuesday resigned from his position. He said he has 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 Columbia University. Panagariya said that about two months ago he informed the PM of his desire to be relieved by August 31. He added he had to make a choice as it would not be possible for him to get the job he had been doing at Columbia University. At US universities one can teach as long as one's health permits. "If I were at 40, then I would have got a job anywhere... the kind of job I have at Columbia is almost impossible to get at this age," he said. The Indian-American, who joined as the first Vice Chairman of Niti Aayog in January 2015, is the second high profile academic-economist after former RBI Governor Raghuram Rajan to quit a top job in India to return to the teaching profession in the US. The 64-year old Panagariya, professor of Indian Political Economy at Columbia University, did not have a fixed term at the government think tank.