Land use can be changed
desperate people can do desperate things. But desperate people with no fear of regulation and no knowledge of the consequences of their action would definitely do desperate things that cause irreparable harm. Consider the case of how developers in Mumbai are buying real estate to build residential complexes on lands there were, till recently, polluting industrial estates. These sites on which new (perhaps plush) residential complexes are being constructed were declared contaminated by pollution control authorities and the industries closed down because they were toxic and dangerous.
It is on this land, which still oozes yellow (unidentified) effluent, that houses will be built for people to live. In all likelihood, builders will promise a paradise