What approval actually certifies
An approved layout has been checked for road width, open space reservation, plot sizing and conversion of the land from agricultural to residential use. The sanctioned plan carries a reference number you can verify.
Approval is what lets a bank finance the plot, lets you obtain a building plan permit, and keeps the resale value intact. Unapproved plots are cheaper for a reason.
Approved vs. unapproved: the red flags
Ask for the approved layout plan and note the DTCP or CMDA approval number and date. Confirm the plot you are buying appears in the sanctioned drawing with the same dimensions.
Be cautious of layouts sold only as 'panchayat approved' when a DTCP or CMDA sanction is required, or where roads and open spaces on the ground do not match the plan.
How to verify before you buy
Cross-check the approval number against the planning authority's records, and match the survey number on the layout to the patta and FMB.
If anything is unclear, get professional DTCP guidance and a legal opinion before paying an advance. The cost of verification is trivial next to the cost of an unapprovable plot.