Order Base-Delta-Zero

Base Delta Zero was the code order for an orbital bombardment to completely destroy a world's life, industry, and natural resources. This was carried out by melting the crust of a planet to a depth of several kilometers, enough to even wipe out deep-planet survival shelters and bunkers. Unlike other Imperial military codes, Base Delta Zero was not subject to change, so that there was never any confusion when it was issued.
Base Delta Zero operations were not used by the Republic until the Clone Wars, although in more ancient times, such razings were known to have been perpetrated by the forces of the Sith.