Why did Zerodha send an email stating ₹1 was refunded?

When a bank account is linked to a Zerodha account using UPI, ₹1 is debited from the client’s bank account to verify that the bank details are accurate and belong to the client. The ₹1 debit is automatically refunded to the client’s bank account within 24 hours. Zerodha also notifies the client via email once the refund has been processed.