I've been to India a few times and seen the mess they've made there. The air is so polluted you can't even breathe it without suffering from headaches and burning eyes. That's the case in large parts of eastern Asia. Too many cars, too many people, all crowded into a small area in extremely densely populated cities. Resources are limited so you can't keep expanding exponentially, at some point you hit the ceiling of resources. It's the same reason we control animal populations. It has to start stabilizing at some point where births=deaths. Technological industrial civilizations are a huge part of the problem, since before that happened, we didn't have most of these issues. The so-called "green" revolution that started incorporating more genetically modified crops, overuse of chemical pesticides and fertilizers has also destroyed the fertility of the soil and depleted its nutrients as the third world is now finding out in Asia and Africa and reverting back to using much more sustainable organic farming techniques.