Where the assessee undertakes levelling work so as to develop the land to facilitate the construction of a building over it, the development and construction of the housing project commences with such levelling of the earth. The expression used is “Commences Development and Construction of the Housing Project”. The intention of the legislature is clear that the development of the project and the construction which follows such development must start on or before the date specified. If either the development or the construction starts before the specified date, the benefit of deduction is not allowable .