How candle can burn in underwater?

A candle can burn underwater if it is placed in a container that keeps the water out, allowing oxygen to reach the flame. The candle's wick needs to be exposed to the air for combustion to occur, as fire requires oxygen to burn. However, if the candle is fully submerged without any air access, it will extinguish quickly due to the lack of oxygen. Special setups, like using a bell jar or a similar apparatus, can enable a candle to burn underwater while still providing an oxygen supply.