what is your vision of The key elements of a healthy and livable city?

The only sources which you need to cite in your explanation are: the text, the video, and the article on Sustainable Cities Index, and Goal 11 (In Shared Documents).
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Considering the fact that cities can be challenging environments for people choosing to live in an urban setting no matter which social class they belong to, whether or not they are a migrant, what is your vision of:
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a) The key elements of a healthy and livable city? How are these achieved?