How to easily unclog a kitchen sink drain?

If your kitchen sink is clogged and you don’t have a plunger but you do have a 2 litre bottle of water and a pair of scissors, you can do this : Cut the top of the bottle off, about 2 inches of it. For a double sink, put the stopper in one side. On the other side,  push the 2 litre bottle of water down and squeeze quickly on the drain.