How have the councils gotten such firm control over the citizens

The Council has garnered complete control over the people by creating fear. The people are afraid of the outside world because of what they've been taught by their teachers and because of the beatings they've endured. Witnessing the Transgressors' death in the courtyard also created fear.

As the chains were wound over their body at the stake, and a flame set to the pyre, the Transgressor looked upon the City.