Strictly speaking, the entire Valrend City is an infection zone.
The safe zone is maintained only around City Hall and its surrounding blocks. Moreover, they struggle to clear more safe zones because the Dandelions can float and move about, and they don't have the resources to keep the safe zone's flames burning at all times, nor do they have enough manpower.
What City Hall could do was to warn all residents through broadcast not to go out, to lock and block their doors and windows, to hide in enclosed environments like bedrooms, cupboards, or basements, and wait for the possible rescue to come.
At the entrance of every building in the safe zone, a bonfire raged, driving away the Dandelions that had breached the outer defenses and drifted into the safe area.
Around some of the bonfires, figures wrapped up tightly, even their heads covered, gathered. Personnel wearing Bird Beak Masks were urging them to approach the fire, one by one removing their outerwear.