ASBA
Market basicsAlso called: Applications Supported by Blocked Amount
Applications Supported by Blocked Amount — the mechanism by which IPO application money is frozen in the applicant's own bank account instead of being transferred to the issuer.
In plain terms
You never send money anywhere. On allotment the block becomes a debit; without allotment it simply lifts, and all you gave up was the ability to spend that amount for a week.