The application of the environmental non-regression principle in Peruvian normative production: Reflections and proposals based on the case of the Inhabitants of La Oroya versus Perú

Aybar J.A.C. · Revista de Derecho Ambiental (Chile) (2026) · DOI: 10.5354/0719-4633.2026.79143

Resumen

The judgment of the Inter-American Court of Human Rights in the case of the Inhabitants of La Oroya versus Peru has highlighted the relevance of the environmental non-regression principle, by holding a State internationally responsible for adopting a regressive environmental measure without sufficient justification. The case concerned the modification of the air quality standard for sulfur dioxide; nevertheless, the standard applied by the Court derives from the duty of progressive development of human rights and the reinforced burden to justify normative setbacks. Despite its relevance, the judgment does not provide a complete methodology to identify regressive measures or assess the sufficiency of their justifications. This omission is particularly relevant in Peru, given its extensive environmental normative production and the absence of an express legal recognition of the principle. This article analyzes the foundations of environmental non-regression, the justification standard required by the Inter-Ameri-can Court, and its express incorporation into Peruvian legislation, ideally through the General Environmental Law. It argues that such incorporation would provide greater legal certainty, reduce transaction costs, and strengthen preventive control over unjustified regressive measures. On this basis, the article proposes an environmental regressivity test applicable ex ante to norms with environmental implications. Finally, it examines implementation challenges in Peru and outlines strategies to ensure ascending and sustained environmental protection. © (2026), (Universidad de Chile. Centro de Derecho Ambiental). All right reserved.

Instituciones: Universidad Nacional Mayor de San Marcos