Environmental Laws: Environmental clearance (EC) for building project – On facts, Project Proponent-construction project made substantial compliance by obtaining the EC from the competent local authority – Subsequent changes in EC regimes – Effect of – Validity of the grant of EC to Project Proponent, challenged to – NGT held that further construction cannot be made without environment impact assessment, but protected the constructions already made by the appellant-Project Proponent on the basis of the EC issued by the Pimpri Chinchwad Municipal Corporation as per the notification – On appeal, held: Project Proponent can legitimately expect a certain degree of stability in the manner in which environmental regime is set and how the applications are processed – Public interest might possibly diminish the degree of legitimate expectation for a party but a balance has to be found – Project Proponent is not expected to anticipate the changes in EC regimes, especially as a result of judicial interventions, and keep revisiting the sanctioned clearances by the competent authority or even raze down validly constructed structures – Neither can it be expected to knock the doors of an authority, not empowered at the relevant time, to process its applications – On facts, the appellant acted on the EC and made substantial investments – They adhered to the applicable legal framework during the concerned period, as such cannot be pushed to a precipice and be made to fall – Doing so would be inequitable – Moreover, third-party interests have also come up –Thus, the order passed by NGT protecting the completed construction is endorsed and four constructed buildings are to be treated to be under a valid EC with all legal consequences – However, for any further construction proposed they must secure fresh clearance as required – Doctrine of legitimate expectation.