If you're in jail and need to sell a flat that has a mortgage, you'll need to involve the bank. The bank holds the title deeds and won't issue a No Objection Certificate (NOC) until the loan is fully repaid. Your wife can approach the bank to arrange the sale, where the buyer's payment will first go towards clearing the loan. You may need to grant your wife a registered Power of Attorney to handle the sale on your behalf, or explore options for attending the registration process from jail.