The correct answer is option-4: Trans-boundary hazardous dumping. The Basel Protocol, also known as the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, is an international treaty designed to control the movements of hazardous waste between countries. Its main objective is to ensure that hazardous waste is managed and disposed of in an environmentally sound manner, minimizing the risks to human health and the environment. The protocol establishes guidelines for the transboundary movement of hazardous wastes, including regulations for packaging, labeling, transportation, and disposal. It also promotes collaboration among countries to prevent the illegal dumping of hazardous waste in developing countries. The Basel Protocol plays a crucial role in regulating and preventing environmental pollution and health hazards caused by the improper disposal of hazardous waste.