This is the most common form of mitigation. In homes with a basement, slab, or crawlspace with concrete floor, suction is pulled from beneath the slab. This are is then routed above the eave of the home. This ensures the radon gas will not reenter the home in harmful concentration.
A membrane is laid over dirt and gravel floors and a suction loop is installed. The suction loop is then tied into the fan and the radon gas is routed safely out of the home.
Suction can sometimes be applied to the existing sump crock. The sump crock serves as a suction pit and often times is the termination point of the drain tile beneath the slab. Suction is applied to the sealed sump and gases are routed safely away from the home in a similar fashion to the above activated systems.