Did you take title search 

whether such search revealed any such registered sale deed kindly clarify 

- As per law, a registered sale agreement is not a tile deed for claiming ownership of the property. 

- Further, as you have already received the NOC from the DC and the Mutation is done in your name ,it means that there is no dispute over the property in the eye of the government authority. 

- It is possible that the said agreement was executed by the previous owner but the transaction was cancelled 

- You should be sure about the pendency of the case if any , otherwise you should take physical possession of the property. 

File a suit for declaration of title and for recovery of possession in a civil court. 

Dear Client,

In your case,i just want to clarify you that, the registered sale deed between you and the District Collector and the NOC that confirms your status as a legal owner will stand in your favour.As per the  Section 6 of  Transfer of Property Act, 1882 the Registered Sale Deed is not affected by subsequent mutation as far as the conveyance of a freehold estate is concerned. The Rights of the other parties based on 20 year old registered agreement of sale cannot automatically vest him with ownership rights. Section 54 of the Transfer of Property Act,1882 grants ownership only upon a registered sale deed, but an agreement to sell merely indicates an intention to transfer property.

If the other party has not filed a suit to enforce his claim over a period of two decades, then this might further fall within the limitation under the Limitation Act, 1963, because the suits for specific performance shall be filed within three years from the date of fixed performance. The possession taken by them is illegal because the deed of transfer is invalid.

You can sue for ejectment against the occupier. In any event, as litigation is already pending, you should engage an attorney to intervene in the litigation to plead your interest under the registered sale deed. Your NOC and mutation now further strengthen your claim; you may even seek an injunction to restrain any further interference with your possession.

Swift action in court will be taken to ascertain your rights as the rightful owner.

Thank you.Hope this answers your query.

Sale agreement is not a title document even if it was executed by a registered deed.

You have a registered sale deed, have mutated the property to your name and also obtained NOC from DC, hence it indicates that you have clear title on your name.

You may file a suit for ejectment to eject him from the property and for recovery of possession on the basis of title deed standing on your name.

File FIR, 

agreement of sale dies not give title. 

Dear Sir,

         You have following options:

1. You can implead as a party to the pending case, if any.

2. You may file a suit for declaration and recovery of illegal possession held by such party. 

3. Please check what type of case he had file because suit for specific performance can be file only within 3 years from the date of execution of alleged sale agreement. First get a set of entire documents and plaint in respect of pending suit then accordingly built up your defense.