Report from China's CCTV
There are 11 million people in Wuhan and it's where the coronavirus originated. The city has also suspended public transportation and long-haul bus links.
From Hu Xijin from the Global Times:
Shutting down outbound transportation of a provincial capital city is unprecedented in China since 1949. Didn't do so even during SARS in 2003. This is a forced step since virus is expanding fiercely. It will greatly increase the chance of epidemic being contained.