How does publish-subscribe design pattern establish loose coupling between components? C#

If was going through a C# exam book and I read:

A popular design pattern (a reusable solution for a recurring problem) in application development is that of publish-subscribe. You can subscribe to an event and then you are notified when the publisher of the event raises a new event. This is used to establish loose coupling between components in an application.

It got me wondering that what does this have to do with loose coupling? Is it only because the components are now not interacting directly or do we have more reasons?