Costa Rica's new president has announced a plan to ban fossil fuels and become the first fully decarbonised country in the world. Carlos Alvarado, a 38-year-old former journalist, made the announcement ... during his inauguration. Decarbonisation is the great task of our generation and Costa Rica must be one of the first countries in the world to accomplish it, if not the first," Mr Alvarado said. Symbolically, the president arrived at the ceremony in San Jose aboard a hydrogen-fuelled bus. Last month, Mr Alvarado said the Central American country would begin to implement a plan to end fossil fuel use in transport by 2021 - the 200th year of Costa Rican independence. "When we reach 200 years of independent life we will take Costa Rica forward and celebrate ... that we've removed gasoline and diesel from our transportation," he promised during a victory speech. Costa Rica already generates more than 99 per cent of its electricity using renewable energy sources. Costa Rica's push towards clean energy faces no large-scale backlash, in part because the country has no significant oil or gas industry. But demand for cars is rising, as is use of other transport systems, and that may prove one of the biggest challenges in meeting the new goal. Transport is today the country's main source of climate changing emissions.