I believe that Miami, Florida is currently the most eco-friendly city on Earth. Soy fuels are very popular throughout. What do you think is? Let's discuss.

sry but not one single city in the usa can be called eco friendly. same goes for whole americas i guess...

Well depends if you look at the city as a whole or as parts. Every downtown isn't eco-friendly. In Hong Kong as an example, being at Sai Kung (Eastern Hong Kong, where there is minimal building development) is like heaven while being in Central (the financial hub of Hong Kong) is like hell when it comes to a point of view of an ecologist.

Copenhagen, Denmark.

Every downtown isn't eco-friendly.

Why?
What kind of concept of eco-friendly do you have?
A house in the middle of a large green area is eco-friendly and downtown HK isn't? Wrong.
Just consider the transportation. Downtown HK is very dense as you know, and the fuel consumption per person is very low.

Well, don't make it every, but most :)

My standard of "Eco-friendly" is that its, as the name suggests, is eco friendly, meaning that it doesn't pose any form of pollution to nature, which is practically impossible for a "city".

However, meeting that requirement means that it isn't even a city. So by my guess, is that your meaning of "Eco-friendly" is a city that acts "The most friendly" to nature. In that case, I don't know which, lol.

^^
Once i was using a program that very easily and approximately calculates the heat dispersion of the walls of a house. Well, the best result is when there are no walls:colgate:

The first place in Japan is Kamikatsu.
kamikatu did 0 garbage declaration.
The classification of the garbage is 36.
The dust cart does not run.
There is not the incinerator, too.
The kitchen garbage processor is set up in all houses.
kamikatu comes for a visit from the world.

Passive House Standard has the least dispersive walls.

Soy fuels have an extremely high ecological footprint actually.