Why is the bank insisting on production of environment clearance certificate for residential housing loan?
Or whether you have mistaken encumbrance certificate (EC) for environment clearance certificate.
If the builder is not cooperating to provide the required documents for obtaining housing loan then you can decide about cancelling the sale agreement and demand for full refund of amount paid by you because it is fault for not complying with the requirements.
You issue a legal notice demanding the certificate or to cancel and return your advance amount.