you are absolutely right!
my criteria for judging a green city is as follows:-
1. the level of development of technology
all green cities have/should have a level of developed technology that will enhance the city's ability to keep the environment safe and green.
2. Population control
we all know that the increasing population of the world is the reason of many ecological reasons we are facing today such as global warming, water pollution, scarcity of basic necessities, etc.
the lesser the population the more land would be occupied and that land could be used for ecologocal purposes, thus, making our cities clean and better.