Why is air essential for burning?

If you limit the amount of air available, the candle's flame eventually goes out once it uses up all the oxygen. Air is essential for burning fuels as oxygen is an essential component for burning or combustion process and oxygen is composed in the air so air is essential for burning fuels.

Air contains about 21 percent oxygen, and most fires require at least 16 percent oxygen content to burn. Oxygen supports the chemical processes that occur during fire. When fuel burns, it reacts with oxygen from the surrounding air, releasing heat and generating combustion products (gases, smoke, embers, etc.).