Southern Action on Genetic Engineering has alleged that Bt cotton has done little to increase yield.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/bt-cotton-has-done-little-increase-yield
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/business-line-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/gm-crops
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bt-cotton
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/genetic-engineering