Charge Density vs Charge Carrier Density

In P-type or N-type semi-conductor type material, the charge carrier density (density of charge carriers aka holes or conduction electrons) varies, the charge density is zero.

However, in Depletion region where the charge carriers are depleted, the charge carrier density is zero while the charge density is not.

In other words, depletion region is carrier-free but not charge-free.