Abatement of customs duty applies to damaged or deteriorated goods through proportionate valuation and reduced duty calculation. Abatement of customs duty is available where imported goods are proved to have been damaged or deteriorated before or during unloading in India, or in specified cases after unloading but before examination, or for warehoused goods before clearance for home consumption, provided the damage was caused by accident and not by wilful act, negligence, or default of the importer, owner, employee, or agent. Duty is then charged in proportion to the reduced value of the goods, and that value may be determined by the proper officer or, at the owner's option, by sale and use of the gross sale proceeds as the deemed value.