The neutral zone or field-free region of a magnetic field refers to an area where the magnetic field is very weak or nearly absent. In this zone, the forces from opposite poles of a magnetic field balance each other out, so there is no net magnetic effect.
In the context of Earth’s magnetic field, the neutral zone can be found along the equator of the magnetic field, where the Earth’s magnetic field lines are horizontal and the vertical components cancel each other out. As a result, the field strength is weaker in this region compared to other areas where the magnetic field is stronger and more directional.