Congestion, pollution, crime, and disease were prevalent problems in all urban centers; city planners and inhabitants alike sought new solutions to the problems caused by rapid urban growth.
In the cities of the developing world, where population growth is outpacing the ability to provide the necessary infrastructure and services, the most serious environmental problems are expected in the immediate vicinity, with serious economic and social impacts on the urban population. Inadequate water supply to households, the accumulation of waste and unhygienic conditions require large claims in terms of unnecessary deaths and illness of one billion of the world population who lives in slums.
Economic problems for many countries in Europe in the 1920s and 1930s were mainly caused by "<span>B. World War I," since this war left many countries torn apart in terms of their economies. </span>
