What is threatening the nature? Air and water pollution, overharvesting of plant and animal species, overpopulation and so on. Overpopulation is the biggest source of pollution. Let's take overpopulation as an example.
What does overpopulation feel like? When we move slowly through the city in a tazi. When we enter a crowded slum district. When the temperature is high and when the air is thick with dust and smoke. The streets are crowded with people. The streets seem alive with people. People eating. People washing. People talking. People sleeping. People visiting each other, arguing and screaming. People relieving themselves. People pushing their hands through the taxi windows, begging. People leading animals. People, people, people, people. As we drive slowly through the crowd, sounding the taxi's horn, the dust, heat, noise and cooking fires made it like a scene from hell! I admit, frightening.