clamp down

clamp down  {v.},  {informal}
To put on strict controls; enforce rules or laws.
After the explosion, police clamped down and let no more visitors inside the monument.
The school clamped down on smoking.
When the crowds became bigger and wilder, the police clamped down on them and made everyone go home.
Categories: {informal} {v.}

'clamp down' on video