This article was printed and downloaded from the RePEc online archive (Research Papers in Economics). It was originally written/published for the Gujarat Institute of Development Research in Ahmedabad, Gujarat, India, and was then published in the Elsevier journal Ecological Economics, issue 49, 2004, p187-198. This article is also available online at www.sciencedirect.com and through www.elsevier.com/locate/ecolecon.