Combustion, characterized by intense chemical reactions generating light and heat, does not always depend on the presence of oxygen.
Magnesium is capable of burning even in carbon dioxide gas;
Metals such as aluminum and copper can combust in sulfur gas, with heated copper wire yielding a black substance;
In a chlorine atmosphere, elements like hydrogen, copper wire, iron wire, and phosphorus are combustible, with hydrogen emitting a pale flame when it burns in chlorine.