Shri T. Armstrong Changsan is a career diplomat with over two decades of experience in the Indian Foreign Service, having served in various capacities in Japan, Nigeria, South Africa including as Ambassador of India to Iceland, his last assignment. In India, he was in the United Nations, Economic and Social Division and also for around 4 years, he was the Regional Passport Officer looking after the North Eastern States.

He joined in December 2021 as the Joint Secretary (PSP) & Chief Passport Officer in the Passport Seva Programme Division of Ministry of External Affairs that administers The Passports Act 1967 through the 36 Regional Passport Offices, 93 Passport Seva Kendras and 428 Post Office Passport Seva Kendras across India, as well as around 180 Missions/Posts abroad.
He has been appointed as part-time end-user representative Director from Ministry of External Affairs on the Board of SPMCIL w.e.f. 3rd March 2022.