[linuskendall]

In this way it almost seems appropriate to rely on country statistics - sure there may be political motivations to label certain places a certain way, but they are also more likely to capture local variations as to what is considered urban and not. I live in a place that is semi-rural by Indian standards but which definitely qualify as urban by EU standards.

[itsmenotyou]

That really depends on what goal you're trying to achieve. If your goals are efficient distribution of aid, or tracking city sustainability across countries, it probably doesn't matter to you what the local variations in the definition of "urban" are.