Battle of Sector Six

The Battle of Sector Six, also known as the Battle of Pawa, was an engagement between UNSC and Covenant Loyalist forces. It took place east of the Afghan town of Pawa, near the current Pakistan-Afghanistan border. The exact coordinates as seen in Halo: Combat, Part 1 are 32°53′12″N, 69°27′48″E.

Background
The ODST pair, Bravo-21 and Bravo-22, were tasked with calculating the crash site of the Master Chief on Earth, while a Marine Battalion was assigned the objective of defending a narrow corridor between Covenant and UNSC forces in Pakistan. Bravo 21 and numerous Marines were killed in the fighting, and Bravo 22 was injured along with many of the other Marine survivors. The battle is referred as "a mission that may secure the salvation of the entire galaxy", and it indeed was: Bravo-22 was able to track Master Chief's landing point with a laser designator, allowing the UNSC forces to quickly locate the Spartan and use him for stopping Truth's plans.

Trivia

 * The battle is first seen in the Halo 3 short, Halo: Landfall.
 * In Halo 3, Master Chief is seen falling out of the sky during nighttime, but in the video of this battle, the Marines track him plummeting towards Earth during the day, which means that the crash zone and the battle are in different time zones. Indeed, the Master Chief ends up falling near Mount Kilimanjaro in Africa, far from the location of Sector Six.