[1] Among his prominent books are Bahudha and the post 9/11 World and The problem of change: a study of North East India.

After an incident involving the extension or resignation of the celebrated Indian Police Service officer Kishore Kunal, he was removed from the post of Home Secretary by the then Prime Minister Atal Bihari Vajpayee who was displeased with his conduct and made the Health Secretary.

Singh served as Executive Director and Ambassador at the World Bank during 1999-2002 representing India, Bhutan, Bangladesh and Sri Lanka and was one of the founder members of the Development Gateway Foundation (DGF) and member, Global Environment Facility (GEF), Washington D.C.

Singh has authored six books including The Problem of Change-A Study of North-East India (1987); India’s Culture: The State, the Arts and Beyond (1998) and Bahudha and the post-9/11 World (2008), all published by Oxford University Press, New Delhi.

Singh has also been Chancellor of the Central University of Tibetan Studies, Sarnath for six years and Chief Editor of the South Asia Series on "Perspectives on Economics, Technology and Governance" of Oxford University Press, New York (2000–06).