This was something of a problem in America a few decades ago. People thought nothing of just throwing trash along the roads, in parks, etc. Informal dumps were everywhere on vacant lots, in roadside ditches and ravines. This eventuality motivated the Keep America Beautiful anti-littering campaigns that are credited with changing public attitudes.

But in 3rd world countries where the priority is shelter and food, it's going to be hard to muster up a lot of concern about litter.