has grown to over seven billion people, and more people live in large cities than in the past.
look for jobs in big cities because they have more businesses, ports, transportation, and educational institutes.
As more people move into cities, the land prices rise, and taller buildings are constructed to accommodate the new residents and businesses.
to provide services, such as water, electricity, and trash collection and disposal, are needed to cope with increasing population.
Also, caused by increased number of cars on the streets need to be dealt with.As more people live and work in large cities, need to be solved.