Provisional attachment to protect revenue permits temporary seizure of property pending customs proceedings, subject to authorised extensions. A customs officer, with prior written approval of the Commissioner of Customs, may provisionally attach property of a person against whom proceedings under section 28 or 28B are pending, under rules made under section 142. Such provisional attachment ceases after six months but the Chief Commissioner may extend the period for reasons recorded in writing, subject to an aggregate cap on extensions of two years; time during which a settlement application before the Settlement Commission is pending is excluded from the extension period calculation.