Answer:
The Order is a group of wizards, led by Hogwarts headmaster Albus Dumbledore, dedicated to fighting evil Lord Voldemort and his followers. ... Harry used magic to fight off the dementors, and since underage wizards are not permitted to use their wands outside of school, he must face a disciplinary hearing at the Ministry.
Explanation: My summary is on the book Harry Potter - Order of Phoenix
