The old idea that cities are destroying the environment has been challenged now with new data and changing paradigm of what it means "a good life". More recently we used to think that the wilderness was not only beautiful and pristine but it was the objective of all human activity. That environmental restoration had the purpose of bringing back the conditions lost by human intervention and waste. Development of our society had produced a plethora of sub-products, second-hand, undesired effects caused by the "ignorance" of developers.
In particular the industrial revolution based on the control of powerful natural energies that brought a rapid increase on the productivity of good needed for our survival. It also brought a dramatic increase of efficiency in the way we do war and destruction. None of this could have happened if not for a better understanding of nature given by scientific advances in all areas. The physical sciences in particular where "energy" and "power" are daily studied, and new forms and mechanisms for their production, control, storage, distribution, and use are being developed. A case in point would be the production of electric power using wind turbines.
So in this context it was that cities were catalogued as necessary evils for the well being of society but people with economic means will tend to move to the outskirts of the city the so called suburbs where they would enjoy the pleasures of nature. Then the end of the twentieth century brought the fact that we could have livable cities and the concept of a "green metropolis" was developed. For more on this read David Owen's Green Metropolis (Why living smaller, living closer, and driving less are keys to sustainability).
In this book we read how New York is in many ways less harmful to the environment than any suburban area based on the fact that one of the most damaging effects caused by humans in modern society is the air pollution generated by our transportation.