(c)[ any new machinery or plant installed after the 31st day of March, 1983, but before the] [Inserted by Act 11 of 1983, Section 11 (w.e.f. 1.4.1984).] [1st day of April, 1987] [ Substituted by Act 23 of 1986, Section 7, for " 1st day of April, 1988" (w.e.f. 1.4.1987).][, for the purposes of business of repairs to ocean-going vessels or other powered craft if the business is carried on by an Indian company and the business so carried on is for the time being approved for the purposes of this clause by the Central Government.] [Inserted by Act 11 of 1983, Section 11 (w.e.f. 1.4.1984).]