The environmental setting and possible influence of global environmental change, including that of climate change, have been presented for coastal and marine environments of South Asia. This has been dealt with in seven sections. In the first section biogeochemistry of the North Indian Ocean with emphasis on the reducing conditions and sensitivity of mid-ocean and coastal systems was presented. In the second, air-sea fluxes of climatically important gases from these marine ecosystems were assessed with particular reference to their contributions to total regional (that include anthropogenic) emissions. Coral reefs of Bangladesh, Sri Lanka and India and the impacts of El Nino and climate change on these systems were reviewed in the third. The Bengal delta, the Sundarbans and mangroves systems were dealt with in sections four to six, respectively. In the last section, impacts of climate change were assessed for the region.