Despite a new UN regulation banning heavy fuel oil (HFO) in Arctic waters, loopholes and exemptions are allowing many ships to continue using this polluting fuel. The ban, intended to protect the sensitive Arctic ecosystem, faces challenges from countries like Russia, which has a large fleet and is not planning to implement the regulation. Environmental groups warn that the ban may not significantly reduce HFO usage for another five years, leaving the Arctic vulnerable to its harmful emissions and spill risks.