community vitality is simply(as i know) strong and active participation of community.
definitely, one person cannot bring about a huge difference. we all have to do our own bit. there is a popular saying single drops together make a sea.
i think community participation and collective efforts are much more productive, not only for developing a green city but for any change that is above individual levels(i.e.community oriented)
from attaining independence to eradicating social evils it was possible because the whole society participated in it and if not, at least wanted it to happen.
hence i totally agree with Urja and Jeeval that a green city can not be created without community vitality.
it is a compulsory step which we can't skip.
but it should not be made the criterion for judging a green city.
how much productive community vitality turns out in a particular area and what levels of it are present will determine whether a city is green or not.
a city practicing community vitality may not be green because it maybe, is in earlier stages and the outcomes are yet to be achieved.
hence in my opinion, which can be wrong as well, community vitality is a step and we should focus more on outcomes than steps.
it is essential but we should not completely rely on it.