(BEIJING, Jan. 24) -- Beijing adopted four major measures to tackle the city's air pollutions, officials said at Wednesday's press conference.

Shi Hanmin, director of Beijing Municipal Bureau of Environmental Protection, said air quality control is the key to the environmental protection.

According to Shi, the city continued to adopt precautions for air pollutions. The energy structure had been improved in order to control the carbon soot, Shi said.

The city had also done a lot to manage the auto vehicle pollution. In 2006, 15,000 taxis and over 3,000 buses were eliminated while 4,000 natural gas driven buses were put into operation.

Additionally, the city had taken actions against industrial pollution. Coal burning boilers in the downtown area turned to use clean energies. The Shougang Group's No. 2 coke oven and coke plant were closed and the desulphurization facilities were put in operation at coal burning power plants.

The fourth measure was to control the pollution of flying dust.

As a result, the city's SO2 emission dropped to 175,500 tons in 2006 from 190,600 tons in 2005.