Which approach to pollution control has shown dramatic results in decreasing pollution?

The approach that has shown dramatic results in decreasing pollution is the combination of markets for pollution rights and regulation. This method is often referred to as cap-and-trade systems. In these systems, regulatory authorities set a limit on emissions and distribute or auction off permits that allow companies to emit a certain amount of pollution.

The market aspect incentivizes businesses to innovate and reduce their emissions efficiently. Companies that can reduce pollution at a lower cost can sell their excess permits to those that face higher costs for reduction. This flexibility encourages cost-effective ways of reducing overall pollution levels. The regulatory component ensures that there is a strict limit on total emissions, which is crucial for achieving environmental goals.

Such a combination effectively harnesses market mechanisms while ensuring compliance with environmental standards, leading to significant decreases in pollution levels and fostering technological advancements in cleaner practices.