After several years of effort to replace large diesel-powered buses with the natural gas CNG buses, the Ministry of Environment announced on April 15, 2003 that more than 3000 CNG buses are already operating in some of the major cities. This is about 15% of the total of 20 thousand buses nationwide.

Recognizing the seriousness of the air pollution situation in our nation, the Ministry of Environment has implemented a "CNG Bus Supply Plan" beginning from 2000, in order to lower the level of air pollutants in large cities. Since large diesel-powered vehicles like buses and trucks are the main culprits of air pollution in large cities, the Ministry has been pushing ahead with its plan to equip large cities with the CNG buses, which emit no exhaust fumes and 70% less ozone pollutant emission, to ameliorate the air quality.

Despite excellent environmental nature and safety, in the beginning, there were many difficulties in supplying the CNG buses in our nation. In the first stages of the plan, only 58 CNG buses were on the roads at the end of 2000. However, due to variety of measures by the Ministry, such as economic incentives for CNG bus purchase and support funds for the fuel and increase in the number of the refueling stations, the number gradually increased to 744 by the end of 2001. The number drastically increased to 2,746 by the end of 2002, and finally as of April, 15, 2003, the number reached 3,025. Seoul City possesses 951, the most number of CNG buses, followed by 504 in Gyeonggi, 319 in Incheon and 318 in Daegu.

The Ministry of Environment expects that due to the widening gap between the cost of natural gases and diesel fuels, and the new measures for the mandatory CNG buses supply, the number of CNG buses on the roads should be able to reach 5000 by the end of this year.