BEIJING, July 30 -- Beijing and neighboring Hebei Province and the coastal city Tianjin will build electric vehicle charging posts on four expressways in the region this year as part of a campaign to promote electric vehicles, authorities said Thursday.

According to Gao Peng, deputy director of Beijing Municipal Commission of Development and Reform, these charging posts will be placed at least every 50 km along four expressways linking Beijing, Tianjin and Hebei Province, a region jointly referred to in China as "Jingjinji," where authorities are pushing for greater integration in transportation, economic development and environmental protection.

More charging posts are expected to be built on other major transport arteries and parking lots in the region in the next two years.

The move came as governments in the Jingjinji area are promoting electric vehicles as an alternative to gasoline-fueled cars among the public to address air pollution in the region.

Emissions from cars have been blamed as one of several factors leading to the choking smog blanketing the region's skies.