Hong Kong is set to become a beacon for hydrogen innovation in mainland China, with plans to legalize hydrogen for vehicle use as part of a strategy to combat carbon emissions. The city's environmental authorities are committed to promoting hydrogen innovation, envisioning a future where vehicles run on hydrogen, emitting only water vapor. Secretary for Environment and Ecology Tse Chin-wan highlighted the importance of Hong Kong's alignment with the country's hydrogen development strategy, emphasizing the potential for carbon neutrality and economic growth. The city plans to introduce new legislation by 2025, including amendments to the Gas Safety Ordinance and the establishment of hydrogen energy certification based on international standards by 2027. The strategy includes the deployment of grey, blue, and green hydrogen technologies, with a focus on green hydrogen produced from renewable sources. Although costly, green hydrogen is seen as crucial for achieving long-term environmental benefits. Hong Kong has already initiated several trial projects, such as a hydrogen-powered bus by Citybus and plans for hydrogen refueling stations and supply facilities. These projects are part of a larger effort to align with Beijing's emphasis on hydrogen energy development, as demonstrated by President Xi Jinping's visits to key regions promoting the industry. Local environmental groups advocate for increased collaboration with mainland China in hydrogen technology to further drive innovation and sustainability.