Advice regarding house

Hi sir,
My father had given our flat in West Delhi to my mother's brothers in 1988 on good faith and without any rental agreement.
They have never asked for any rent from them.
My parents started asking them to vacate the flat 10 years back but they kept on making some excuse or another and finally now they have started claiming that the flat belongs to them.
My parents have the ownership documents.
Please advise if a legal case can be put on them and what are the chances that they can get the flat back.

yes. you can file a suit for possesion against them.
you'll have to state that your father allowed him to live in the suit property as permissive user with undertaking that he would vacate the same whenever asked by your father.
also answer as to who, is paying all the property taxes on that property and telephone and electricity bills are on whose name?

You can contact me at isidjain1@gmail.com.

Thanks for the answer.Property taxes are filled by by father and electricity bill is also in the name of my father.

File suit for Declaration along with possession and mandatory injunction. ( Please enclose all the documents which you have in regards to that property). It will roughly take 3 to 4 years. 

But remember one thing to have to pay court fees according to your property value.

Thanks,

Regards,

Aman Chawla