An official with the Ministry of Industry and Information Technology (MIIT) Monday urged domestic and foreign firms to strengthen cooperation to develop the country's electric car industry.

It was China's policy to encourage more foreign firms to increase cooperation with Chinese companies so both can enjoy the opportunities offered by China's burgeoning green economy, said Gao Dongsheng, deputy head of the energy conservation department of the MIIT.

Green vehicles were key for the development of China's auto industry as auto exhaust emissions already accounted for 70 percent of the country's air pollution in major Chinese cities, said Wan Gang, Minister of Science and Technology, in an interview with Xinhua in October.

Wan said China's electric car output would reach one million units by 2020, as the country's total auto sales were expected to top 17 million units this year.

Chinese firms still lagged far behind world-class international enterprises in electric car technology and management, and cooperation and independent innovation was encouraged, Gao said at a press conference about the International High-tech Exhibition of Green Industries and Green Economy, to be held in Beijing starting Wednesday.

The four-day event will be attended by 127 participants, 85 of which are foreign-funded firms.