It would be an exaggeration to call this the world's slowest fire rescue, because I can easily imagine fire rescues being slower (hey, at least the traffic is moving!), but let's all agree that if you want to be rescued from the Central Business District, it's best not to have an accident at rush hour.
The below video was taken just a little after 5 pm on Thursday, with big plumes of dark smoke clearly visible against a pale blue sky:
The fire began in the "afternoon," according to Xinhua, and as you'll notice because of the timestamp in that linked article, it was still ongoing at 6 pm. A friend of mine who works near CBD said the fire went on for about two hours before any firetrucks got to it.