Whether OC will be taken as date of acquisition or agreement for sale will be considered

Is oc occupancy certificate, Date of acquisition 

As per ITAT, date of allotment is to be considered as date of acquisition.

Nor OC neither allotment letter to be considered as date of acquision. However allotment letter and further payments to builder or any other authority can be considered for capital gain indexation. 

only registered / non registered  sale agreement (Registry of property) can be considered as date of acquisition.