Yellow-zone cities were usually the satellite of their green-zone city counterpart. Neyta, as a yellow city for a green-zone that became the center of commerce in the Eastern Federation, was filled with companies and factories. It was boisterous and full of energy, a never-ending work to make sure logistical distribution was done right.
Projo, as the satellite of the capital city Rexon, was calmer in comparison. It was the biggest yellow-zone city, but not the most populated. The infrastructure was great because it was directly managed by Rexon, and the cityscape was made to be as neat as possible that it almost bore no difference from a green-zone city--except for the absence of the high wall.