In Belgium, in addition to the competences of the communities and the regions granted constitutionally, specific responsibilities are established by regional decrees (on Environmental Regulation, or VLAREM, Integrated Water Management, etc.). Finally, some countries have ad hoc mechanisms outside legislative frameworks for allocating responsibilities at the sub-national government level. For instance, in Mexico, there are villages where daily simple or complex activities of communities, such as the organisation of drinking water assemblies that do not fall under the jurisdiction of municipalities, are subject to customary law.