whose career has been in the USA. Varadhan obtained his BSc (in 1959 with record marks) and MSc (1960) from Madras U. His PhD supervisor at the Indian Statistical Institute was Rao. In 1963 Varadhan joined the Courant Institute of Mathematical Sciences in New York, where he has remained. He is a member of the AAAS (1988), the NAS (1995) and was elected FRS in 1998. He was President of the IMS in 2003, its Rietz Lecturer in 1987 and its Wald Lecturer in 2005. He was awarded the 2007 Abel Prize (the mathematics equivalent of a Nobel Prize).

http://bulletin.imstat.org/2011/11/s-r-s-varadhan-profile-of-the-national-medal-of-science-recipient/ Fuller biography.