Should over populated countries implement policies similar to the China one child policy?

Well, there are positive as well as negative effects of one child policy also. Population growth is one of the major positive impact, I will not go into the positive impacts rather will focus on the negative ones.

China's one-child policy was successful in nearly halving the fertility rate over the past three decades, but has brought with it a slew of negative side-effects, including a rise in sex-selective abortions and infanticide.

Some other reasons include depression faced by the single child in the house, when there are 2 children, the chances of depression and related issues is less as compared to single child.

Well to put it this way, I believe that for sure we have to control population on this planet and today population is becoming or is already a big issue for us. But forcing people for single child is also not a very good solution.