The poorest places in the world were the tropics: it is very hot there, land is not in good condition, water is no where to be seen, and diseases are very powerful. In this scene, a poor couple are not happy were their living conditions.
LDCs have unfair trade with the MDCs, it was unbalanced and the LDCs could not compete. The MDCs just wanted the LDCs natural reasources. This man is concerned about the products being taken to a MDCs.
Over population occurred when the growth of population overcomes their resources. In this scene, as you can see, there are many people over crowding the environment.