Amortisation of preliminary expenses allowed across successive years for specified start up and expansion expenditures, subject to prescribed conditions. Amortisation allows an Indian resident assessee who is an Indian company or a person other than a company to deduct specified preliminary and setup or expansion expenditures in equal instalments over five successive tax years starting with the year of commencement or the year the extension or new unit begins operations, subject to a statutory ceiling measured against project cost or capital employed, prescribed reporting requirements, audit obligations for non company assessees, continuity rules on amalgamation/demerger, and prohibition on claiming the same expenditure under any other provision.