Question

why buffer stock is created by the government

Answer 1

To feed the poor who can't afford food or to help the needy during disaster or natural phenomenon

Answer 2

To ensure availability of food to all sections of the society, the Indian government carefully designed food security system, which is composed of two components: (a) buffer stock and (b) public distribution system.

This is done to distribute food grains in the deficit areas and among the poorer strata of society at a price lower than the market price.