Air China has blunt advice for tourists visiting the British capital.
It is generally a safe city, the Chinese state airline's inflight magazine tells its readers - "but precautions are needed entering areas mainly populated by Indians, Pakistanis and black people".
The comments have already caused what London's Evening Standard newspaper described as a "racism storm".
They appear to have been spotted by a Chinese journalist, Haze Fan, who tweeted a picture to London Mayor Sadiq Khan, adding that her Londoner fiancée found it "rather insulting".
The Evening Standard reported that some British politicians are already demanding an apology and that the phase be removed from the magazine, where it appears in both English and Mandarin.