Land Dispute

My friend had a 5,4acre of vacant land. For site planning he had obtained the approval and the map from Tamil Nadu town planning authority. But had not sold the property under plan approval. He had sold the only 5 acre to third party. Now he has now 40cents of land only. But now the local punjayath told the balance 40 cents belongs to local punjayath based upon the plan approval. How can he claim the unsold 40 cents. Pls give the suggestion.