Two features of the right to health are key to understanding the importance of health impact assessment in realizing the right to health. First, the right to health is subject to progressive realization. Many states do not have the resources necessary to fully implement the right to health immediately. Nonetheless, states must take deliberate, concrete and targeted steps towards the full realization of the right to health. The corollary to this obligation to progressively realize the right to health is that there is a strong presumption that retrogressive measures in relation to the right to health are not permissible