He served Assistant Professor, Associate Professor and Professor at University of Wisconsin at Milwaukee during 1967-77. He was a Post-doctoral Fellow in Public Utility Economics during 1971-72. In 1976 Dr. Malcolm Adiseshiah, Vice-Chancellor, University of Madras invited him to join as Professor of Economics at University of Madras. He joined the University in 1977 and started M.A (econometrics) course in 1978. He was a Visiting Professor at National Institute of Public Finance and Policy, New Delhi in 1992. He was a Visiting Fellow at the Australian National University, Canberra in 1999. He was the Founder-Director of Madras School of Economics during 1994-99 and continues there as Honorary Professor since 2000.
He was President of the Indian Econometric Society in 1993-94. He was National Coordinator of the World Bank funded Ministry of Environment and Forests' Capacity Building Programme in Environmental Economics during 1997-2002. He He was part-time member State Planning commission, Tamilnadu, 2001-4. He was ICSSR National Fellow in 2003 and 2004. He received UGC Swami Pranavanada Saraswathi National Award in Economics for 2006. He was a member Government of India Delegation to UN Conference on Sustainable Development at Rio de Janeiro, June 2012. He is currently Chairman, Editorial Advisory Board, Sarvekshana , NSSO, Ministry of Statistics and Programme Implementation..
He has published papers in Review of Economic Studies, International Economic Review, Journal of Economic Theory, Review of Economics and Statistics, Journal of Asian Economics, Journal of Energy Development and other journals. He has published many books and reports. His recent books include Controlling Pollution: Incentives and Regulation, (with Shekhar Mehta and Sudipto Mundle), Sage Publications; Environmental Economics ,Oxford University Press; Economic Reform and the Liberalization of the Indian Economy (editedwith K.P Kalirajan) ,Edward Elgar; Economics of India’s Space Programme , Oxford University Press,; Trade and Environment , Oxford University Press; Eco taxes on Polluting Inputs and Outputs (with Raja Chelliah, Paul Appasamy and Rita Pandey), Academic Foundation; and Development and Public Finance, (edited with D.K. Srivastava), Sage Publications.