Using the absolute population size? If so, is America far more "overpopulated" compared to every other developed nation? If China were to split up into 20 sovereign nations, would it suddenly stop being overpopulated?
Or perhaps you're using population density? If so, Taiwan, South-Korea and Netherlands must be absolute cesspools to live in, since they all have population densities higher than India's.
Or more likely, you think that a country is overpopulated because it has a lot of poor people? If so, that sounds like a mighty fine circular reasoning. "Why is XYZ so poor? Because they are overpopulated." "What makes you say they are overpopulated? Because they are so poor."