On this day, 27 years ago, on August 12, 1998 (June 21, 1998, the first batch of dual-fuel buses in Beijing were put into operation. On August 12, 1998, more than 60 buses that can use both liquefied petroleum gas and gasoline drove onto the streets of Beijing, marking the beginning of the use of clean fuels for buses in Beijing City. Drivers of dual-fuel vehicles use liquefied petroleum gas fuel first during operation and use gasoline after the fuel is used up. This environmentally friendly dual-fuel vehicle has no different appearance than ordinary cars. After simple technical transformation, it has added a liquefied petroleum gas tank and a corresponding fuel supply system. In order to protect the capital's environment, Beijing City Public Transport Corporation plans to modify 1000 dual-fuel vehicles and build supporting gas stations within the year.