(You should probably check the law on this before you actually break the lease. I think the premise is that they actually broke the lease by reducing the value of your holding, without providing a replacement or even giving you reasonable notice.)
Don't assume that if they break the lease, you are allowed to break it too.
In at least one place, the law is:
If your landlord deprives you of a quarter of your apartment*, you have to keep paying for the other three quarters; that is, the lease is not considered void.
Avoid using the court system to back you up if you can - the law might not be on your side and even if it is, it can be a huge headache (and expense) to get courts / government to do anything useful for you.
Disclaimer - consult a lawyer if you want to know the law in YOUR situation.
*due to a construction project, broken roof, or something like that