internal migration(A population shift occurring within national or territorial boundaries, often characterized by persons seeking labor opportunities in more advantageous areas)
internalisation of external costs(The process of getting those who produce goods or services with adverse effects on the environment or on society to incorporate a knowledge of possible negative repercussions into future economic decisions)
international agreement(Cooperation in international efforts to support global environmental goals. Solutions to environmental problems such as trans-boundary airborne and waterborne pollution, ozone depletion and climate change require action by all responsible countries)