Procedure for Issue/ Validation and renewal of Certificate of Airworthiness
http://dgca.nic.in/ftppub/D2F-F3.pdf ( The first page has some important info)
Procedures Relating to Registration/De-registration of aircraft
http://dgca.nic.in/ftppub/D2F-F1.pdfhttp://dgca.nic.in/aircraft/air-ind.htmNo mention of rules regarding DIY scale aircraft. Rules/procedures have been stated for Organizations to manufacture aircraft but not for Individuals as such.
Contacting DGCA(preferred) or sending an RTI can you help you to get details.
And think building a prototype or a college project and testing/demo wont need approvals if intention is not to use it in civil airspace for personal or commercial use, otherwise you will also need a pilot license,equipments such as radio's and whatnot.