What does it mean that civil air defense should be allocated to construction areas?

Hang guidance signs for elevators, stairs, and main entrances and exits during wartime at conspicuous positions at the entrances of civil air defense projects. The walls and columns of the air-proof basement that should be built should be painted orange to mark the scope of the civil air defense project. Parking space signs should be hung above the motor parking spaces, and the words "Civil Air Defense" should be sprayed in the parking spaces.

In the smaller areas that should be built, a narrow ribbon should be sprayed 20 centimeters above the ground, with the words "Civil Defense Walls, Destruction Strictly Prohibited" written inside. The over-provisioned walls and columns in the civil air defense project are painted with two orange-yellow ribbons to mark the over-provisioned areas.