This discussion addresses whether it's possible to claim a TDS refund for past financial years (AY 14-15 to AY 20-21) even if income tax returns haven't been filed. The consensus is that claiming a TDS refund is possible, subject to certain conditions. These conditions depend on the source of income and the specific section under which the TDS was deducted. A refund can potentially be claimed for up to five years prior, plus the current year, after an application and verification of income sources and their taxation by the Assessing Officer.
You can take 5 year refund and current year refund if you're allowed by Ao after the application and details verification of income source and it taxation