Government 'may sanction nerve-agent use on rioters', scientists fear

Darts filled with very highly concentrated THC. (At massive doses, THC makes people fall asleep, but doesn't do any other harm)

Darts filled with either liquid '___' or ecstasy. '___' if it was highly concentrated, would make people unable to continue rioting, or even walk, because they'd be hallucinating to the point where they wouldn't know what was real. Ecstasy would make people just want to hug each other, or lie down.