Police pepper spraying peaceful protesting students

The way the police did things in this video was obviously wrong except the leaving part...I can't believe the police would do that they are there to protect not enforce.

https://www.youtube.com/watch?feature=player_embedded&v=BjnR7xET7Uo#!

Were the protesters blocking a road or something? Using pepper spray does seem a little extreme but it's likely that the police asked them to move beforehand.

EDIT: I looked more closely and it appears to be a walkway, not a road. Seeing as people could just walk around/over them, I see no reason for the police to forcefully stop them like that.