Delayed / late / behind schedule

[pizza]

I know that to express a delayed state of a project I could use behind schedule but I am not sure if it can be used in the following case as well:

The teacher said: "my classes (progress) are behind schedule."

How else can I say this?

[5jj]

The teacher said: "my classes (progress) are behind schedule."

How else can I say this?

That seems to me to be the best way to say it.

[pizza]

I see.

I was looking for an alternative verb / expression to convey a delay in terms of work or production rather than time. I guess this is it then.