Why was the money debited from the bank account before the scheduled transaction day?

Funds are debited from the bank account before the eMandate transaction date to ensure that they are available in the Zerodha (trading) account on the specified date of the transaction. Funds need to be debited from the bank account at least one working day in advance so that the balances reflect in the trading account on the transaction date.

Funds transferred through eMandates take 1 day to show up in the trading account. This is because the money is debited from the bank account during banking hours, but the National Payments Corporation of India (NPCI) credits Zerodha’s bank accounts and confirms the transaction at the end of the day.