Agricultural subsidies are grouped in one of three boxes (green, blue or amber) at the WTO, depending on the degree to which they distort trade. Green box subsidies are permitted because they are deemed to cause minimal distortion, and typically include those to research and development (R&D), environmental protection and animal welfare. Blue box subsidies are also permitted, but on the condition that they must not lead to increased production.
Meanwhile, all domestic support considered to distort production and trade (with some exceptions) falls into the amber box, which is defined in Article 6 of the AoA as all forms of domestic support except that placed in the blue and green boxes. Included in the amber box are measures to support prices, and subsidies directly related to production quantities. Amber-box support is subject to limits expressed in terms of a "Total Aggregate Measurement of Support" (Total AMS) which combines all supports for specified products, together with supports that are not for specific products, into one single figure.
Whether subsidies deserve to be placed in the green or blue box, rather than the amber box, is sometimes a matter of contention at the WTO. Within the current negotiations, many developing country members have expressed concern over "box-shifting": the movement of subsidies from the amber to the blue box without significant changes in the nature of the subsidy. The G-20, a group of 20 developing country WTO members, has pushed for rules that would help ensure that amber box subsidies are completely transformed before gaining access to the blue box.
