Combustion is a chemical reaction in which a combustible or flammable substance reacts with a gas (which is a supporter of combustion, for example oxygen), releasing heat. The reaction is exothermic in nature. Necessary factors required for a combustion reaction to take place are:
1. A combustible or flammable substance. For example wood, petroleum, etc.
2. Ignition temperature. The fuel must be at or above this 'ignition temperature'.
3. A gas that is a supporter of combustion (oxygen). An abundant supply of such a gas is required.