Wikipedia
HCNG
HCNG (or H2CNG) is a mixture of compressed natural gas and 4–9 percent hydrogen by energy. It may be used as a fuel gas for internal combustion engines and home appliances. HCNG dispensers can be found at Hynor ( Norway) Thousand palms and Barstow, California, Fort Collins, Colorado (all US), Chongqing and Shanxi ( China), Pico Truncado ( Argentina), Islamabad ( Pakistan), Dunkerque ( France), Gothenburg Sweden, Rio de Janeiro ( Brazil), Emilia-Romagna, Lombardia ( Italy), Dwarka and Faridabad ( Delhi), India and the BC hydrogen highway in Canada.
HCNG for mobile use is premixed at the hydrogen station.