The above clip is from “When heaven burns” (天與地) and “this city is dying, you know?” in the “locust” ad comes from this drama. As you can see from the clip, the reason behind its ban in China is due to the political messages it sent. Dr Dylan (the green shirt man) is played by Joe Junior, who is of Chinese-Portuguese ancestry. A mixed ancestry actor pronounced the dead of this mixed ancestry city. How appropriate!
The following is the ending song for the drama, 年少無知 (Young and Naive). It contains metaphors of Tiananmen Massacre and Hong Kong Handover.
It was also sung during Dolce & Gabbana protest.
Dictionary of Politically Incorrect Hong Kong Cantonese 
[…] with the mainland, both political and otherwise. We see it in videos and signs saying, “this city is dying.” We see in calling mainlanders ‘locusts.’ We see it in the colonial flag being […]