NOVELTY - The apparatus (101) has a central enclosure comprising inner and outer walls to define an annular space between the inner and outer walls, where the space includes an inlet (2) on the outer wall to receive air from an external blower/fan. A supply unit supplies fuel to the enclosure till an upper limit of a gasification zone. The inner wall includes spaced apertures to be arranged in a circumferential path extended up the inner wall to provide air to gasification and combustion zones. An ash door is placed at a bottom of a gasification/combustion chamber to hold the fuel and removal of ash.    USE - Apparatus for performing gasification and combustion of fuel e.g. solid fuel such as bio-fuel (claimed), in a multi-condition acceptable advanced biomass gas reactor. Can also be used for firewood, coal, refused derived fuel, rubber waste, leather waste, coconut husk, coconut shell, coconut fronds, mango seed, cow dung, powdery bio-fuel and agrowastes.    ADVANTAGE - The apparatus combines operational advantages of countercurrent and co-current gasification, and can be operated on all types of fuel to be briquetted or pellet form converted to a free gas by removing ash and particulate in a proficient manner, while handling optimum size, extreme moisture and high bulk density feedstock in proportion with low bulk density feed materials like leafy trash/powdery feedstock e.g. sugarcane trash and bagasse, and agro-waste materials in bailed or briquetted forms and accommodating any type of feedstock feed on optimum size with higher bulk density that is highly comparable over woody feedstock and powdery feedstock and acceptable with large woods and large sticks with higher moisture acceptability. The apparatus allows oxidizing agent inlet temperature for sustained gasification to be achieved at ambient temperature regimes and at extreme temperatures below 28 degree Celsius without any pre-heating process, so that rating capacity with feedstock can be doubled, while using wood chips or pellets under pressure below 300 milli-meter of water column and the gas reactor with moving gate mechanism with adjustable options based on size feedstock for gasification can be designed and operated at low speed to minimize char ash generation, thus achieving a very high gasification efficiency.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for performing gasification and combustion of fuel.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of an apparatus for performing gasification and combustion of fuel.    Fuel inlet (1)    Inlet (2)    Apparatus for performing gasification and combustion of fuel (101)