why is hydrogen a clean fuel?

Hydrogen is considered a clean fuel that has a minimum impact on the environment nearly eliminating the levels of carbon dioxide and other greenhouse gas emissions. It is safe to manufacture, reliable and environmentally friendly. In its molecular form hydrogen can be used directly as a fuel to drive a vehicle, to heat water or indirectly to produce electricity for industrial, transport and domestic use. The huge advantage that hydrogen has over other fuels is that as a fuel it is non-polluting, when you combust hydrogen the only product is water.