Conversion of rural agricultural land into residential plots and subsequent sale of plots?

Hi

What are the Implications on conversion of rural agricultural land into residential plots and subsequent sale of plots?

agricultural land is ancestral property held from more than 100 yrs ago.

Example:
step 1:
Rural agri land converted to residential plots .this is not a capital asset so no Capital gains .

step 2: in the same year plots are sold .
now,
1.anything above fair vale will be business income .

2. upto FV, diff between FV and cost of acquisition will be short term capital gain. what will be the cost of acquisition. ?

if fair value on the day of conversion is cost of acquisition and it is sold in the same day for the same FV,then there is no Capital gains .

please clarify.

Thanks