Ministry of Environment and Forests (MoEF) has issued a Guidelines for declaration of Eco-Sensitive zones around National parks and Wildlife Sanctuaries, based on the decision taken by the National Board of Wildlife. These guidelines have been framed to facilitate the States/ Union Territory Governments for declaration of Eco-Sensitive Zones around National Parks and Wildlife Sanctuaries.
It is available at their site here. http://moef.nic.in/downloads/public-information/Guidelines%20for%20Eco-Sensitive%20Zone.pdf