Public International Law (Vol. I & II)
Article 62
A fundamental change of circumstances may not be invoked as a ground for terminating or withdrawing from a treaty unless the existence of those circumstances constituted an essential basis of consent and the effect of the change is radically to transform the extent of obligations still to be performed.
This ground may not be invoked if the treaty establishes a boundary or if the fundamental change is the result of a breach by the invoking party of an obligation under the treaty or another international obligation owed to another party.