On 23rd March 2023, Busan's mayor Park Heong-joon announced a plan to build the Busan Express Rapid Transit (BuTX), a new 47.9 km underground line that will run with hydrogen-powered trains at speeds of up to 180 km/h. The line will connect major districts with the new Gadeok Airport and cost an estimated €84.84 billion (KRW59 trillion). According to local media reports, the plan could face criticism as a feasibility study conducted between January 2021 and December 2022 was only partially passed. The construction of the line is intended to support Busan's application to host EXPO World Expo in 2030.
