Hydrogen is a gas and the most common chemical element in the universe. It is colorless, odorless, neither harmful nor hazardous to water. Hydrogen is the element with the lowest density.
Besides applications in many industrial processes e.g. in the chemical industry, hydrogen is an excellent source of energy that can gradually replace many petrol-based internal combustion engines. When hydrogen is burned, mostly water is produced, but no CO2 or particles.
Hydrogen can be produced locally by means of electrolysis – i.e. the separation of water into oxygen and hydrogen by means of electricity – not only in industrial plants but also, depending on the quantity required, locally. This eliminates long, polluting transport routes.