The way to prevent such 'unevenness' in rules intended to help the environment is to make them taxes and caps on emissions, rather than bans.
If for example the US were to decide we need to halve mercury emissions every 5 years for the next 50 years (a 99.9% reduction), then we would implement a system where anyone emitting mercury needed to purchase the 'right' to pollute by auction. Each year the available quota would be reduced.
The end result is the levels of pollutants are reduced in the most economically viable way.
If for example the US were to decide we need to halve mercury emissions every 5 years for the next 50 years (a 99.9% reduction), then we would implement a system where anyone emitting mercury needed to purchase the 'right' to pollute by auction. Each year the available quota would be reduced.
The end result is the levels of pollutants are reduced in the most economically viable way.