What is the difference between the World network of biosphere reserves and biosphere reserves?

World network of biosphere consists of the important biosphere of ecological value, nominated by states, included in it by UNESCO.but a country can announce a biosphre reserve on its own which may or may not be included in the network of the biosphere reserve

In simple terms, all biospheres in the list of network of biosphere reserve are biosphere reserves in their state but the reverse is not the case.

Ex: In India, there are 18 biosphere reserves but in the network of biosphere reserve there are around 10 only.