How does the economics law of diminishing returns apply to population clean-up ?

im not good in this help?How does the economics law of diminishing returns apply to population clean-up ?
It is just like cleaning your house. If you spend 5 hours cleaning up it may look a lot better. But if you do 10 hours it will look better still but not quite as dramatically so. 15 hours etc. etc. Every 5 hours makes it somewhat better but the improvements get smaller and smaller.





No one can tell if you clean the dust from the tops of the doors but you will know so you better do it.





In environmental clean ups there is plenty of gain to do stuff that stops making people sick. Next it may just make the environment look better but it costs money/resources. Prevention will cost money also. Someone must make the decisions about where the improvement is not worth the cost.