Tax recovery undertaking supports no objection certificate, binds employer to certified liability and authorises recovery without prior proceedings. A prescribed undertaking supports issue of a no objection certificate under section 420(1), by which the employer or other specified person undertakes to pay taxes that are or may become payable in respect of income earned during employment and income received by the person leaving India. The form requires employer and traveller particulars and provides that any amount certified by the Assessing Officer as due shall be treated as conclusive evidence, while the undertaking remains binding despite death, dissolution, or liquidation and permits recovery by the Central Government under the prescribed rule.