Social development means the continuous improvement of the welfare of a population—taking place side by side with economic development, being supported by that development and, in turn, supporting it. But economic development which leads to social and political stability cannot progress very far with an illiterate, apathetic, undernourished, and disease-ridden population.
In contemporary under-developed areas where rapid industrial expansion is induced, parallel changes in other sectors and other aspects of national life may lag far behind and fail to provide a basis for an integrated process of social and economic development. The result is apt to be a situation—found in many areas of Asia, Latin America and Africa, as well as in parts of Europe—in which modern urban industrial societies exist side by side with traditional rural societies but show few signs of close integration with them. This contrast has been accentuated in some countries by the fact that the industrial sector was established by representatives of a foreign culture, or closely modelled upon a foreign culture. The existence of a gulf between the modern industrial society and the traditional agrarian society may have important social repercussions for both sides, particularly at point of contact, when elements of the rural population move towards the cities or when the products of the factory begin to reach into the countryside.
Virtually every country in the world, developed as well as developing, has a segment (or majority) of its populace suffering from social underdevelopment.