But this is not how humans are wired in the real world.
What you want is clear anti pollution policies, good laws and very high penalties, combined with very efficient supervision/execution.
Countries where financial penalties for water pollution are highest and where the culprits get caught
and penalised end up with cleanest waters.
nations neither have the ecological conscience, clear policies, nor are executing whatever they might have.
Water quality varies from dirty to very dirty, depending on where you are.
People in their mass will not stop polluting, unless it hurts them financially.