It is a quite common practice for investors in large capital development projects to seek a special status for their approved development plan, such that their project will be exempted from certain existing laws (particularly environmental provisions), or future laws or regulation, or government actions, that would alter the basis upon which the project was to be developed and operated from that envisaged in the approved development plan. In most instances, the special development requirements will be passed as an Act of Parliament, or amendment, or as an Indenture Act relating solely to that project.
The existence of such exempting provisions has allowed long-term pollution by outdated plant to continue unchecked by later stricter pollution standards.