You should register the certified copy of HC judgment in your favour 

2) Submit the document to the Sub-Registrar office where the property involved in the case is located, as per Section 28 of the Registration Act, 1908

3) Fill out a standard application form provided by the Sub-Registrar office, including details like the case number, parties involved, property description, and the specific relief granted by the HC judgment.

4) The Sub-Registrar may verify the authenticity of the judgment before registering

You issue a legal notice to them for this and then proceed legally through court for necessary relief.

The owner should not suffer due to their negligence 

Mutate on the basis of HC order. File consumer case against DDA for hefty compensation. 

- You can issue a legal notice after giving the details of High Court Judgment , and ask for the transfer papers for the purpose of mutation . 

- If refused or no response, then approach the Court against the DDA. 

Dear Client,

To go further with the change on the property due to the research on untraceable files from the DDA and a favourable high court judgment, start by compiling all the documentations in relation to the judgment, a proof of possession of the property and the communications made to the DDA. The formal mutation application has to be filed to the local municipal authority or revenue department and it is mandatory to enclose the High Court Judgment and other documents like proof of identity and tax receipts etc. Support your case on mutation based on a court decree using the Cooperative Societies Act. Ensure you follow up your application periodically and if it is rejected or stuck, approach the court by filing a complaint with a higher authority with jurisdiction or proceed to court. You can also seek legal representation from a property lawyer when going through the process of mutation so as not to compromise their ownership rights.

Hope you find this advice beneficial.