Overpopulation is a hard problem. There are complex socioeconomic reasons for why some countries have higher fertility rates than others. This is a heavily studied topic in health economics, but I am unwell right now and do not feel like digging through research papers. Instead, I will point you to a wikipedia article that talks about one (popular with economists) take on overpopulation:

http://en.wikipedia.org/wiki/Demographic_transition

Sorry for the wikipedia link, but it is not a half bad article on the subject and it was easy to find. Basically, this theory suggests that increased income per capita is correlated with a decrease in a country's fertility rate.

There are arguments on both sides regarding the flow of causality, but if you wanted to know what was being done to address the challenge of overpopulation then that article above is a good starting point for your own inquiries.

(Also, just as a side note, it is probably the case that you were down-voted for being off-topic and not due to some overwhelming sentimentality. Maybe if you want to talk about overpopulation you should have written a blog post and posted it up, I bet that would have probably got a much better reception.)