[4][5] He was honoured by the Government of India in 1971 with Padma Shri, the fourth highest Indian civilian award.
Thereafter, he worked at the Indian Archive where he had the opportunity to work under renowned educationist and former Union Minister of Education, Triguna Sen.[3][5] In 1958, when the Sikkim Research Institute of Tibetology, present day Namgyal Institute of Tibetology (NIT), was established, Sinha was appointed as its founder director.
[3][5] He worked there till his retirement in 1987 after which he moved to Siliguri and took up the post as the Centenary Professor of International Relations at the University of Calcutta.
[3][5] During his tenure as the director of NIT, Sinha contributed significantly to the Bulletin of Tibetology, a bi-annual publication by the institute.
[3][5] Namgyal Institute of Tibetology honoured him by compiling his selected works which was published as a book in 2008 under the name, A Tibetologist in Sikkim.