anti-riot       
adjective (also antiriot) uk/ˌæn.tiˈraɪ.ət/ us/ˌæn.taɪˈraɪ.ət/
 防暴动的
intended to prevent or control a riot (= a large number of people behaving in a noisy, violent, and uncontrolled way in public)
  The situation eased after 1,000 anti-riot police officers were deployed. 在部署了1000名防暴警察后,局势有所缓和。 
 Thousands of police officers in antiriot armour stood guard along major roads. 
 - More examples
- Protestors clashed with anti-riot police on Tuesday night.
- Police officers and anti-riot troops looked on as a small group of protestors defied the ban.
- Police in antiriot gear cordoned off several streets in the city centre.