The principle of non-regression has both ecological and legal dimensions: it can be defined as a prohibition on state conduct that results in environmental degradation or in the weakening of environmental laws. The non-regression principle originates in international human rights law and may be viewed as “a negative obligation inherent in all positive obligations associated with fundamental rights” including human and environmental rights. At the theoretical level, non-regression is closely related to other key tenets of environmental governance including the precautionary principle, sustainable development, the principle of intergenerational equity, and the right to a healthy environment. Non-regression has been understood as an aspect of the constitutional right to a healthy environment, recognized in at least 147 constitutions around the world. Non-regression has also received significant support in several important non-binding instruments of international environmental law.