Question

w why we should not throw medicines oils or fats in the drain

Answer 1

Drains ultimately open into large water bodies, where there is abundance of aquatic animals and plants. Presence of medicines, oil or fats in the drain water, is harmful to the aquatic life. Especially oils and fats form a fine layer over the water surface and prevent the entry of oxygen essential for life, into the water. Medicines contain chemicals which may be toxic to the life there and sometimes may even cause choking.

These are few reasons why such substances should not be thrown in the drain.

Answer 2

because it causes water pollution.and v. dangerous for aquatic animals.