Is indexation available on sale of unregistered property

The date of booking / date of allotment will be the date of acquisition of the property. And the period of holding starts from that date.

indexation is available.

You have a right in the property and anytime at the earliest you can register it .

The buyer may object and hesitate to buy bcoz of unregistered property and impending stamp duty liability and registration charges (which will surely arise at the time buyer and seller goes for registration.)

if you had made any purchase agreement on 2010 and the payments were made through banking channel, then date of booking can be reckoned as date of purchase and INDEXATION can be availed. before that work out Ltcg taking 2010 as date of purchase as well as stcg by taking 2019 as purchase date (after registering the property in your name). whichever is beneficial to you, go for that.

1. From the tax angle, the above sale will surely attract capital gains tax. As the wording given in sec 2(47)(v) says that once the "any transaction involving the allowing of the possession of any immovable property to be taken or retained in part performance of a contract of the nature referred to in section 53A of the Transfer of Property Act, 1882 (4 of 1882)" 
2. From the above explanation, it is clear that once the possession of the property is taken it will be regarded as sale and subsequently capital gains will arise from the same. 
3. But as explained by experts above it will be a problem at the time of sale of such property. With respect to indexation benefit, it will be available from the date of possession of such property as per the above explanation. 
4. If an agreement was entered which says the property gets transferred only upon the payment of final installment then indexation will be available only from 2018. However, it is based on the agreement of sale. If the rights and possession get transferred upon payment of the first installment then indexation will be available from 2010. 
5. Advice would be to register the property before initiating the sale. 
Please correct me if the above solution has an alternative view.