Biosphere reserves serve as pollution markers. By studying the composition of biosphere reserves we can tell what pollutant is caused by humans. Currently, there are 18 biosphere reserves in India. These are protected areas for the conservation of plants and animals. Out of these 18 biosphere reserves, 12 are recognized as part of “World Network of Biosphere Reserves”.

Each biosphere reserve is divided into three zones: core zone, buffer zone, and manipulation zone. A core zone is a legally protected area where human activities are not allowed. It is the innermost or central zone. In buffer zones, limited human activities are allowed only for research and educational purposes, this area is presented outside the core zone. The manipulation zone is the area where human activities are allowed like cropping, forestry, and settlement. The manipulation zone is the outermost area. Out of 18 Indian Biosphere Reserves, 12 are part of the World Network of biosphere reserves.