clamp down
phrasal verbclamp down (on somebody/something) 
- to take strict action in order to prevent something, especially crime严厉打击(犯罪等) - a campaign by police to clamp down on street crime警方严厉打击街头犯罪的运动 
- The US government is clamping down on drugs.美国政府正在取缔毒品。 
- to clamp down hard on bullying严厉打击恶霸行为 
 
- a campaign by police to clamp down on street crime