Step 1: Understanding the Basel Convention
The Basel Convention is an international treaty aimed at reducing the movement of hazardous waste between nations, specifically from developed to developing countries. This treaty was adopted to protect human health and the environment from the harmful effects of hazardous waste.
Step 2: Analyzing the Options
Option (A) talks about all nations assembling for a common environmental problem, but the Basel Convention focuses specifically on hazardous waste management.
Option (B) discusses CO2 and CH4 emissions, which are related to global warming but are not the focus of the Basel Convention.
Option (C) focuses on acidic gases causing acid rain, which is not the primary focus of the Basel Convention either.
Option (D) is the correct one because the Basel Convention specifically deals with the trans-boundary movement of hazardous wastes.
Thus, the correct answer is (D).