Poor air and water quality, insufficient water availability, waste-disposal problems, and high energy consumption are exacerbated by the increasing population density and demands of urban environments and obvious urban growth and sprawl.
Some of the major health problems resulting from urbanization include poor nutrition, pollution-related health conditions and communicable diseases, poor sanitation and housing conditions, and related health conditions. These have direct impacts on individual quality of life, while straining public health systems and resources. Urbanization has a major negative impact on the nutritional health of poor populations. Because they have limited financial resources and the cost of food is higher in cities, the urban poor lack nutritious diets and this leads to illness, which contributes to loss of appetite and poor absorption of nutrients among those affected.
These are just a few of the many downsides to urbanization. While not everything about urbanization is negative of course the depth of discussions to be had about the various aspects are almost infinite. Your question was a tad vague and didn't give specifics as to what you were looking for so I hope my answer helped.
Mutual defense alliances was a significant cause for starting World War I. Basically, what happened was all of the countries were somehow alliances with other countries. Conflict between different countries caused the allied countries to be involved which eventually led to World War I.
