WTO Members have the right to adopt measures to protect the environment...
Under GATT rules, WTO Members can adopt measures to protect the environment and human health and life as long as such measures comply with GATT rules, or fall under one of the exceptions to these rules. This right to adopt measures has been affirmed by panels and the Appellate Body time and again. In the US — Gasoline case, for example, the Appellate Body concluded that “WTO Members have a large measure of autonomy to determine their own policies on the environment (including its relationship with trade), their environmental objectives and the environmental legislation they enact and implement...[and] that autonomy is circumscribed only by the need to respect the requirements of the General Agreement and the other covered agreements”.
As long as the measures are justified under GATT Article 20
Article 20 on General Exceptions lays out a number of specific instances in which WTO Members may be exempted from GATT rules. Two exceptions are of particular relevance to environmental and human health protection: Articles 20(b) and (g) allow WTO Members to justify GATT— inconsistent measures if these are either necessary to protect human, animal or plant life or health, or if the measures relate to the conservation of exhaustible natural resources, respectively. In addition, the chapeau of Article 20 safeguards against the misuse of trade measures by providing that in order to be justified under Article 20, measures must not be “applied in a manner which would constitute a means of arbitrary or unjustifiable discrimination between countries where the same conditions prevail, or a disguised restriction on international trade.”
> Secretariat background note on how GATT Article 20 is applied to environmental measures in WTO dispute settlement rulings.