Question

why we should not throw oil and fats in the sink

Answer 1

Cooking oil and fats should not be thrown down the drain.They can harden and block the pipes.In an open drain the fats clog the soil pores reducing its effectiveness in filtering water.

Answer 2

Answer:

Oils and fats harden and block the sewage pipes. In an open drain also,fats block porosity of soil which affects it's water filtering efficiency. That is why oils and fats should not be released in the drain.