Hi Nithin,
It's a good question you asked. As per my knowledge,First confirm the approved plans from the appropriate authority are in place. Check that all other permissions from various authorities are in place. E.g. Utility Companies, Environment clearance, Airport Authority, etc. Confirm that the Land title is clear and there is no disputes/litigation (Title Certificate).
Hi Nithin , In my point of view, Confirm Builder has the Intimation of Disapproval (IOD) and commencement Certificate (CC) to start construction. Have the agreement evaluated by an Advocate. Check possession date promised and provide for penalty if Builder does not deliver as agreed. Check and negotiate the payment schedule. Do not book in Pre-launch without executing and registering the agreement.