The number of CNG buses in operation reached two thousand (10% of total intracity buses) on June 5, 2002 as a result of supplying CNG buses for 2 years and 6 months. Ministry of Environment plans to supply a thousand more buses by the end of this year.

This accomplishment was possible thanks to the Ministry Environment's efforts to provide subsidies for the accompanying CNG infrastructure, including provision of fuel, building CNG refueling stations, and raising public awareness on the safety of these stations.  

Seoul has the most CNG buses in Korea (803), followed by Gyeonggi-do(291), Daejeon(183), Daegu(154), and Daegu(154).

Ministry of Environment plans to expand supply of CNG buses. By 2007, CNG buses will replace all diesel-powered intracity buses. Various CNG vehicles, such as small buses and garbage trucks, are being developed and supplied. In addition, Ministry of Environment carries out to revise the Air Quality Management Act that will make operating CNG buses operation obligatory for the transportation companies.