Eco-Sensitive Zone

Eco-Sensitive Zones (ESZs) or Ecologically Fragile Areas (EFAs) are areas in India notified by the Ministry of Environment, Forests and Climate Change (MoEFCC), Government of India around Protected Areas , National Parks and Wildlife Sanctuaries. The purpose of declaring ESZs is to create some kind of "shock absorbers" to the protected areas by regulating and managing the activities around such areas. They also act as a transition zone from areas of high protection to areas involving lesser protection.
Authority.
ESZs are regulated by central government through the Min. of Environment, Forests and Climate change (MoEFCC). The Ministry came out with new guidelines for the regulation of such areas in 2011.
Statutory backing.
The Environment (Protection) Act, 1986 does not mention the word "Eco-Sensitive Zones". However, Section 3(2)(v) of the Act, says that Central Government can restrict areas in which any industries, operations or processes or class of industries, operations or processes shall not be carried out or shall be carried out subject to certain safeguards. Besides Rule 5(1) of the Environment (Protection) Rules, 1986 states that central government can prohibit or restrict the location of industries and carrying on certain operations or processes on the basis of considerations like the biological diversity of an area, maximum allowable limits of concentration of pollutants for an area, environmentally compatible land use, and proximity to protected areas. The above two clauses have been effectively used by the government to declare ESZs or EFAs.
The same criteria have been used by the government to declare No Development Zones. Time to time, the Ministry of Environment, Forests and Climate Change (MoEFCC) approves a comprehensive set of guidelines laying down parameters and criteria for declaring ESZs. A committee constituted by MoEF puts this together. The guidelines lay out the criteria based on which areas can be declared as ESZs. These include Species Based (Endemism, Rarity etc.), Ecosystem Based (sacred groves, frontier forests etc.) and Geo-morphologic feature based (uninhabited islands, origins of rivers etc.).
Extent of ESZ.
An ESZ could go up to 10 kilometres around a protected area as provided in the Wildlife Conservation Strategy, 2002.
Moreover, in case where sensitive corridors, connectivity and ecologically important patches, crucial for landscape linkage, are beyond 10 kilometres width, these should be included in the Eco-Sensitive Zones.
Further, even in the context of a particular Protected Area, the distribution of an area of ESZ and the extent of regulation may not be uniform all around and it could be of variable width and extent.