Air pollution in Vietnam and predictable deaths

“Why do you decide to leave our country?” I asked some questions like that whenever my friends left me and their country to fly to another land. Different people gave me various answers, but overall, these answers have the same sad point that they aim to relish a better living environment. This answer seems to be ridiculous to me at that time. “It is so weird! A better living environment? We all grew up healthily in this environment, right here in our hometown”. I always wonder myself whenever I think about the above idea. Traffic c…