Democratic U.S. President Joe Biden aims to finalize a rule on a clean fuel tax credit before leaving office on Jan. 20, a senior White House official said on Sunday. The clean fuel program, which would provide credits for the production of sustainable aviation fuel and other lower-emission transportation fuels, is set to begin in 2025. The Biden administration also plans to release a study on the environmental and economic impacts of liquefied natural gas before Jan. 20, the official said.