1. The petitioner, a Hindu undivided family, was assessed to income- tax. In 1968, a plot of land at Chandigarh in sector 17-C was purchased. Constructions were, thereafter, started over the plot in 1969. It continued up to 1975, relevant for the assessment year 1976-77. During the assessment years 1968-69 to 1976-77, the petitioner disclosed investments in the construction of the house at Chandigarh as under:

2. Thus, the total investment up to 1976-77 shown by the petitioner was in the sum of Rs. 7,68,897.

3. Assessments for the years 1968-69 to 1973-74 were simultaneously taken up and completed by the Income-tax Officer, Special Ward, Ajmer, on May 13, 1974. In the said assessment proceedings, the petitioner submitted a letter dated April 29, 1974, detailing therein the amount of investment and sources thereof. He also submitted a valuation report from Messrs. Basant Singh and Company, Engineers, Architects, Ga