It's rather a regulation, not law. And I don't think it's apply to your case, because the regulation I mentioned above only limit recent transactions. That is,

It's rather a regulation, not law. And I don't think it's apply to your case, because the regulation I mentioned above only limit recent transactions. That is, if you brought a house, from the time of the purchase, you can't re-sell it within 2~5 years. After that, you're free to go. If that old condos is not within the limited time, then maybe it is real that the house have no resale value. In that case, as far as I know, the only option is to wait until local government re-sell (re-develop) the land. But don't take my word, I don't know every policy of every local government. If you really curious, ask the question on a Chinese website like zhihu.com, then maybe you can get some information that is more useful.