Chinese technology company Baidu announced on Friday that it had received a commercial license from regulators to operate its self-driving taxis in Shenzhen, a city of more than 12 million people that is also considered China’s technology hub, Reuters reported.

Baidu said its fleet of “robotaxis,” known under the Apollo Go brand, has been approved to operate and collect fares from passengers in a 188-square-kilometer area in Shenzhen.

The tech company first brought its self-driving taxis to Shenzhen last year, but the machines have not been allowed on the roads unsupervised. Driverless taxis were also banned from charging passengers.

Baidu’s new approval comes after the Chinese company previously received the necessary license to operate its robot taxis in the cities of Wuhan, Chongqing and Beijing. In the Chinese capital, however, the company is still waiting for the right to pay.

Baidu also said Thursday that it plans to put 200 more driverless taxis on the road by the end of this year.

Baidu has invested billions in self-driving taxis over the past decade, and the technology has come a long way, and late last year the company even won the right to operate them at night in the city of Wuhan.

Driving at night, in rain, fog or snow is a big challenge for autonomous cars. However, technology has advanced and some cities have decided that these cars can be driven safely even in low visibility conditions.