Protesters have threw rocks and oil onto the Tolo Highway in an attempt to block traffic from a bridge near Chinese University.

This type of criminal acts have happened multiple times. Earlier, multiple cars have been damaged by hard objects being thrown onto highway by the protesters.

Source:

https://hk.on.cc/hk/bkn/cnt/news/20200229/bkn-20200229044323910-0229_00822_001.html