The capital will take 180,000 old vehicles off the road and promote clean energy autos among government departments, the public and the urban cleaning sector, which includes street cleaners and trash collectors, Wang Anshun said at the opening of a session of the Beijing Municipal People's Congress, the municipal legislature.

　　The heating systems of 44,000 old, single-story homes and coal-burning boilers downtown are to be replaced with clean energy, Wang said as he delivered a government work report.

　　In the next five years, "Beijing will complete afforestation of 66,000 hectares to make the city's forest coverage hit 40 percent or above. Its total emissions of major pollutants will continue to be reduced," said Wang.

　　The city will also speed up the promotion of clean energy in rural areas and strictly control dust in construction projects, said Wang.

　　He vowed to strengthen air quality monitoring and analysis, as well as the release of such information.

　　The city also plans to reduce coal consumption by 1.4 million tonnes and volatile organic compounds emissions by 8,000 tonnes, in addition to closing some 450 heavily polluting plants, according to municipal authorities.

　　Earlier this month, several consecutive days of smoggy weather choked Beijing, as readings for PM2.5, or airborne particles measuring less than 2.5 micrometers in diameter, far exceeded safe levels.

　　"The most important is the measures to handle the basic causes. One is the technological upgrading or closure of polluting companies. Another is the promotion of environmentally friendly public transport," said Wei Aimin, a lawyer and municipal lawmaker.

　　"Vehicles contribute about 17 percent of pollution. We should try to reduce vehicle exhaust pollution by all means," Wei told Xinhua. "In this regard, both officials and individuals should make their own contributions."A Chinese netizen calling himeself "chayu2000" wrote on Sina Weibo, a most popular microblog, "The most effective method is to strictly control the number of vehicles belonging to government institutions. Officials should set an example and take buses or commuter vans to work."The number of vehicles has increased to 5.18 million currently from 3.13 million in early 2008, according to the Beijing Municipal Commission of Transport. In 2011, the city began to adopt a license plate lottery system to curb the rapid growth of vehicles.

　　Over the past five years, Beijing built 300-km-long urban rail transit lines with nearly 190 billion yuan (about 30.3 billion U.S. dollars), said Beijing's acting mayor. The total length is 442 km in Beijing, which plans to complete 24 km more of such transit lines this year.

　　"The core issue with Beijing's air quality is the growing population," said Jiang Yi, director of the Energy Saving Studies Center at Tsinghua University.

　　"Currently, the population burden on Beijing's environment has reached maximum levels. Pollution treatment cannot go on without population control," said Jiang, who is also a political advisor attending the on-going annual session of the municipal political consultative body.

　　Beijing's population reached 20.69 million by the end of 2012, an increase of 500,000 people year on year, the Beijing Municipal Statistics Bureau said. The population stood at 16.33 million in early 2008.

　　The city should strictly control the expansion of manufacturing industries to reduce the inflow of workers, the expert suggested.

　　Wang Yingchun, deputy head of the Beijing Municipal Meteorological Bureau, said efforts to improve air quality require the coordination of relevant departments.

　　"The pollutants in Beijing come not only from the emissions in Beijing, but also from those of neighboring cities. Thus, air quality forecasts and early warnings should be cross-regional," Wang said.

　　Wang also advised environmental protection, medical and health and meteorological departments cooperate with each other and share air quality monitoring information.

　　Zheng Zhangshi, another political advisor, said the city should continue to implement the effective pollution control measures adopted during the Beijing Olympic Games in 2008.

　　He said Beijing should offer advanced technologies or management to help upgrade industries in adjacent regions as part of coordination efforts.

　　The Beijing Municipal Air Pollution Control Regulation draft, which was released Saturday to elicit public comments, stipulated emergency measures for heavy pollution days, such as suspension of factory production, and reduction in the number of running vehicles. Violators will face hefty punishment.

　　In 2012, the density of major air pollutants in Beijing dropped by 3.8 percent on average, the Beijing Municipal Environmental Protection Bureau said.

　　In response to public demand, real-time air quality monitoring data on PM2.5 intensity in China's 74 major cities, including Beijing, has been released since Jan. 1. Beijing has set up 35 stations for real-time air quality monitoring of PM2.5.