Orbital bombardment is the use of weaponry from orbit to attack the surface of a planet. The scale of the bombardment may range from precision strikes against single targets to wiping out all civilization on an entire planet through direct and indirect effects, such as radiation.
The surface of the planet Iconia was destroyed through massive orbital bombardment around 200,000 years ago. Only a single structure survived intact until 2365, containing an Iconian gateway. It is speculated that gateway technology allowed some of the Iconians to escape the attack. (TNG: "Contagion") An Iconian ziggurat on Vandros IV was impervious to orbital bombardment due to its neutronium construction. (DS9: "To the Death")
In 1484, the Vaadwaur homeworld was rendered uninhabitable by an orbital bombardment using plasma bombs, conducted by the Turei and their allies. Six hundred Vaadwaur managed to survive underground by placing themselves in stasis. High levels of radiogenic particles still remained in the atmosphere when the USS Voyager visited the planet in 2376. (VOY: "Dragon's Teeth")
In 2267 in the mirror universe, the ISS Enterprise had been ordered to destroy Halkan cities from orbit, if the Halkans refused to allow the Terran Empire to mine dilithium on their planet. (TOS: "Mirror, Mirror")
Starfleet General Order 24 entailed the destruction of all life on a planet from orbit. Garth of Izar, during his insanity, attempted to implement this order against Antos IV in 2269. (TOS: "Whom Gods Destroy"). Captain James T. Kirk also threatened to implement this order against Eminiar VII in 2267. (TOS: "A Taste of Armageddon")
In 2371, the Tal Shiar and the Obsidian Order launched a joint operation to destroy the Founders of the Dominion by bombarding their homeworld in the Omarion Nebula. However, the Founders had infiltrated both organizations and evacuated their homeworld in anticipation. The combined Romulan-Cardassian forces were then annihilated by an overwhelming Jem'Hadar fleet in the Battle of the Omarion Nebula. (DS9: "The Die is Cast")