In WTO terminology, subsidies in general are identified by 'Boxes' which are given the colours of traffic lights: green (permitted), amber (slow down - i.e. be reduced), red (forbidden). In agriculture, the Agriculture Agreement has no Red Box, although domestic support exceeding the reduction commitment levels in the Amber Box is prohibited; and there is a Blue Box for subsidies that are tied to programmes that limit production. The 'amber box' covers all domestic support measures considered to distort production and trade. The 'green box' covers subsidies that do not distort trade. The 'blue box' covers payments directly linked to acreage or animal numbers under schemes which also limit production.