What documents do I need to apply for a DTV visa sponsored by my father in Delhi?

To apply for a DTV visa in Delhi, being sponsored by your father, you should include his 6-month bank statement, three years of Income Tax Returns (ITR), a sponsorship letter, and additional documents including an invitation from your gym for soft power activities. It appears that this documentation is generally sufficient, and you likely do not need an employment contract since you are sponsored and not planning to work in Thailand.