Capital gains reinvestment option permits acquisition of additional residential houses subject to threshold and single-use restriction. Amendment permits, subject to a monetary threshold, an assessee to elect to purchase or construct two residential houses in India and treats those houses as the qualifying 'new asset' for exemption under section 54 by substituting references to one house with two; once this option is exercised in any assessment year the assessee cannot exercise it subsequently for that or any other assessment year.