亮红灯

亮红灯:

Literally means:

show the red light; hinder; ban

Actually means:

红灯, the red traffic light. This phrase figuratively means banning something or interrupting its process officially.

It also refers to setting barriers to hinder or limit the development of something. Usually used to refer to hindering the process or continuance of illegal, illegitimate, abnormal or unhealthy things.

Give warning to the abnormal operation of something.

红灯，表示车辆停止前进的红色信号灯。亮红灯，比喻发出禁令，不准某事进行或中止某事继续下去。也指设置障碍，阻止或限制事情的进展。多指制止违法、违规或不正常、不健康事物的进行或继续。

指对事物的不正常运转发出警告。