Since your mother purchased this landed property by a registered sale deed in the year 1993 and had been in possession and enjoyment of the same and also to prove her title, she was awarded the compensation also by the concerned competent authorities towards acquisition of a part of the land, her title is clear.

Your mother can file an injunction suit against the said person restraining him from interfering in yor mother's possession and enjoyment of the same.She may implead the government department also as a party to the  suit seeking the relief of removal of the restrictions they have passed on this property to the registrar and also for declaration of title to her on the basis of the registered sale deed document.

You may discuss with an advocate in the local and proceed on the advises rendered.

Get details of the land through RTI.

Then it is advisable to work out a legal remedy. 

Regards 

G.Rajaganapathy 

High Court of Madras 

X has dead claim, Onus on him to prove and not your mother. Mother have long possession and even if there was any claim of X , is now barred by limitation.

Challenge the RDO order. Merely on someone`s objection, such direction cannot be issued. And X should have directed by RDO to bring evidence in support of his claim.

NO - govt. cannot.

If govt will take the same under land acquisition you will get the adequate compensation for the same. Govt can acquire land for public good even without conditions. You can approach high court under writ petition if you find any Arbitrary conduct of govt in the said procedure

See the claim of X has to be contested you have to file.reply to his objection you need to show that you were bonefide purchaser and purchased same by veryifying patta document. That you mother is in possession paid taxes and purchased with registered deed. 

Also the terms of patta on which it was purchased need to be perused.

It is necessary to peruse patta to advice as to whether any terms and conditions were attached to patta 

2) your mother can file declaratory suit that she is absolute owner of property and to set aside order of registrar restraining further transactions in property 

1. File suit for mandatory and permanent injunction against Mr X and revenue department for restraining X to claim property and order revenue department to remove all conditions from further transaction of land.

2. Govt will not take over the land as currently the property is on your mother's name. 

Usually, a special tahsildar is empowered by the government to issue pattas for various beneficiaries. You have to find out if any conditions were imposed on the beneficiary while issuing the patta. You may apply under the RTI Act and get the necessary information.