how do you know it does not belong to someone in the block?
how do you know it has been dumped?
the fact that it has been parked off road would imply the person has known they could not use it for a while and have placed it there deliberately.
if they have declared it sorn, then they allowed to park there.
they could have bought it and its broken down, or they plan to sell it, or it needs fixing up etc - if its their parking space too they are allowed to do that.
i would suggest you message everyone in the block asking if its theirs before you touch it - if you move it or have it towed and it belongs to someone they will likely be pretty angry with you and bill you for retrieval of their property.
i would.