While Los Angeles is estimated to have removed 1,000 private vehicles off the road, a Paris-based firm is partnering with the Los Angeles Department of Transportation to supply 200 EVs and 100 chargers on various streets.

"A total of 121,425 EVs have been registered in Shanghai, almost doubling the number 12 months ago," said Ding Xiaohua, deputy director of Shanghai's EV Public Data Collecting, Monitoring and Research Center, or EvData, also affiliated to SIAC.

"All those EVs are being monitored here - the entire EvCard fleet as well as all privately-owned and public ones like electric buses and sanitation vehicles," Ding said in front of a congested e-map of the downtown on a huge screen in an EvData monitoring room in Jiading, a municipal district, where the SIAC is headquartered.

When the center was set up in 2012, he recalled, data came from only eight cars, all hand-recorded. Now the platform is the world's biggest in terms of database size, the number of involved automakers, models of cars and total mileage.

A car's location, speed, battery capacity, voltage and temperature can be produced in just 30 seconds.

While big data can be used for driving behavioral studies and car performance evaluation, accidents can be alerted and prevented when certain parameters are breached, according to Ding.

Professor Roger Raufer, of energy, resources and environment at the Hopkins-Nanjing Center, stressed that China has an "obvious strategic vision" in EVs and clean energy transport.

"Although it is first driven by its own domestic needs for better air quality and fewer oil imports, China's sheer scale and global aspirations make it a tremendously formidable player on the international scene," said Raufer, a former advisor to the UN Division for Sustainable Development in New York.

Last year, over 507,000 EVs were sold in China, more than the combined sales in the United States, Norway, the United Kingdom, France, Germany, Sweden and the Netherlands.