This was exactly the sort of thing the ministers of the G20 sought to avoid when they met in Washington late last year, agreeing not to devise new trade barriers as the world economy fizzles.

• 去年底，二十国集团峰会的首脑在华盛顿会晤，他们极力避免此类事情的发生，就不在全球经济低迷时期制造新的贸易壁垒达成共识。