Seoul City plans to build four additional compressed natural gas (CNG) stations for buses as part of its effort to increase its fleet of environmentally-friendly natural gas-powered buses.

In 2005, there were 20 CNG stations around the city, but the number increased to 43 by 2009.
"Residents near CNG stations opposed the facilities at first, but assured them of the safety of the sites," a city official said. The gas is distributed through city gas pipes.

The city operates a CNG system called "Seoul Clean Station" at the Seosomun Annex of City Hall.
Currently, 88 percent of the 7,600 buses in Seoul are fueled by CNG and 1,089 shuttle buses and garbage trucks also use the natural gas.

The city's clean-air drive paid off last November, when its level of fine-particle pollutants in the air hit its lowest level since 1995.

Seoul City, in cooperation with the Ministry of Environment, Hyundai-Kia Automotive Group and Korea LPG Association, started a hybrid taxi pilot project in December.

"Hybrid vehicles give off fewer emissions, including carbon dioxide, and have good gas mileage," a city official said.

Other large cities worldwide are introducing hybrid taxis to reduce air pollution as well. New York City has already replaced 20 percent of its taxis with hybrids and plans to convert all cabs by 2012.

meeyoo@koreatimes.co.kr