What to do with this delisted stock?

I bought EXCAST in 2017 and then got too busy in other stuff and never checked the stock. Turns out it no longer trades on NSE or BSE. I hold 42488 shares, purchased at 50,000 INR, now worth ~17K according to Zerodha. Can I still sell this somewhere?

The shares of Excel Castronics have been suspended from trading due to penal reasons. You can learn more on this here.

You cannot sell them in the secondary market until it starts trading again. You can however find an willing buyer and do off-market transaction. If not, then you’ll have to write-off this as bad investment.