Diffusion of Innovation States can be seen as policy laboratories. They allow for small-scale experiments with policies. Successful policies can be applied in other states. Some states lead in innovation. Innovation then diffuses over time to other states.
Experience demonstrates that prevention is often more efficient, and effective, than control.
However, pollution control technologies can transfer pollution from one medium into another. This is a fragmented approach to regulation. Many environmental problems are transboundary. For example, air pollution generated by power plants in one state often migrates to others. Some states are more receptive to innovation than others.