The present invention determines gasifier for gasification of MunicipalSolid Waste (MSW). It particularly determines gasification of combustible fraction of MSW to produce fuel gas with high caloric value. The gasifier of the present invention mainly comprises a feed cone (1), a feeder (2), a reactor(3) and a wet discharge unit (4). The present invention determines the gasifier for gasification of MSW for conversion of combustible fraction of MSW into fuel gas by introducing oxidant which are the mixture of oxygen and inert gas that includes nitrogen and argon. The present invention also provides minimal of discharge and the hot gas that can be directly used in all thermal applications both in hot and cold modes including ultra clean applications like cooking and food industries.