Shenzhen's fleet of buses will be 100 percent electric by the end of 2017. There are already some 14,000 electric buses on the streets of Shenzhen, with only a few hundred diesel-powered stragglers left in commission, which will be phased out over the coming months.
BYD, the company responsible for about 80 percent of the city's buses, started testing its electric vehicles in 2011. Back then, the space needed for their batteries occupied the space set aside for passengers, but massive improvements have been made since then. In 2016, BYD became the world's biggest manufacturer of electric vehicles, exporting its wares to over 200 cities across 50 different countries.
China isn't the only country to pursue electric vehicles for its public transportation – by 2019, electric school buses will be available in the US. However, the country has a especially urgent need to phase out gas- and diesel-powered vehicles as a result of its dire air quality.
The Chinese government has been making huge strides toward its environmental goals, and efforts in Shenzhen will help. While the manufacture of electric vehicles does produce emissions, they're largely localized to the production plant, rather than pumped out of exhausts in urban areas.