Implications of residential land area extent is less in patta than that in sale deed

 residential Land area extent is less in patta than in sale deed in tamilnadu;

1. how the difference affect s the ownership of land area mentioned in sale deed

2. why the difference in patta land area

3. how to get patta for the entire area of land mentioned in sale deed.

4. Whether House construction permission will be restricted to land area in patta or as in sale deed