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The United Nations and other international organizations have declared that the 21st century will be the century of "Urban".The ratio of population of people live in urban region estimated to be more than 70％ of the world in 2025.Most of them will live in the cities called "Mega Cities",which area defined as the territory of so crowded and 10 million of population.Especially the most of "Mega Cities" will be located at Asia.