Siemens recently published on their website the European Green City Index showing the results of a study conducted by the Economist Intelligence Unit.
Copenhagen was ranked #1 with Stockholm (2) and Oslo (3). Dense city centres such as Berlin (8), Paris (10) and London (11) scored high on the test. Cities that scored low where Sofia (29) and Kiev(30). These cities scored low as populations have increased and the economies have grown underinvestment in infrastructure has caused crowding on public transport and roads along with other factors such as climate which increase requirements for heating and cooling.
For more information about the study go to the [SOURCE: Siemens - Green City Index]