As the Association of Southeast Asian Nations (ASEAN) becomes an influential actor in international investment rule-making, this article scrutinizes the environmental provisions within ASEAN investment agreements and evaluates their adequacy in preserving ASEAN member states’ (AMS) regulatory autonomy for environmental protection. Through a comprehensive survey of fifteen plurilateral investment agreements, the study conducts a comparative analysis with international treaty practices to determine the effectiveness of these provisions in reconciling environmental concerns with foreign investment promotion objectives. These findings reveal that environmental provisions in ASEAN investment agreements are often vague or narrowly tailored, limiting their ability to provide adequate regulatory space for AMS to implement necessary environmental measures. This article concludes by offering recommendations for enhancing environmental provisions in future ASEAN investment agreements to ensure a more balanced approach safeguarding both investment promotion and environmental regulation rights of AMS.

Contemporary environmental issues require the joint actions of the global community, which may assume many forms but always depend on developed and harmonized national legislations. States develop environmental law by implementing provisions of multilateral environmental agreements into national legislation. However, the implementation process sometimes prevents the effective adaptation of international legal norms. While the structure and mechanism of the implementation process have been frequently discussed from the relationship between international and municipal law, few studies have been dedicated to the implementation process of international environmental norms. Consequently, this study will analyze the implementation of multilateral environmental agreements with special references to the Republic of Kazakhstan. The article will present cases of implementation and the resulting issues in the national environmental legislation of the Republic of Kazakhstan. Moreover, it will examine national measures to solve these issues that will be relevant for all countries with similar ecological questions.