Natural gas vehicles (NGVs) have impressive environmental credentials. They emit no SOx (sulfur oxides), soot or other particulate matter, and compared to gasoline and diesel powered vehicles, their emissions of NOx (nitrogen oxides) and CO2 (carbon dioxide) are relatively low. NGVs come in a variety of types, from minicars to (more commonly) trucks and buses − a feature that sets them apart from other low emission vehicles.
　The number of NGVs crossed the 10,000 mark in November 2001, the 30,000 mark in December 2006, and the 40,000 mark in March 2011. National efforts will continue to be made to promote the spread of NGVs.