Control Population two are enough.

Have only two childs in the family.
Making People Aware of Family Planning: As population of this world is growing at a rapid pace, raising awareness among people regarding family planning and letting them know about serious after effects of overpopulation can help curb population growth.
More people are faced with unsanitary sources of food; disease and famine begin to take root. If left unaffected, it will sweep through an entire population.
World level population growth is a challenge in addressing the global poverty. The population of the world now exceeds the natural resources available to sustain it. Unemployment in the world is a result of population growth.