ORDER :- A three-Judge Bench of this Court in the case of Dr. Balbir Singh v. Municipal Corporation, Delhi, (1985) 2 SCR 439: (AIR 1985 SC 339) elaborately examined the provisions of the Delhi Municipal Corporation Act of 1957 for the purpose of ascertaining the manner of determination of "rateable value" which was necessary for making assessment of property tax under that Act. This Court classified the properties into four categories :-

(1) self-occupied ;

(2) partly self-occupied and partly tenanted;

(3) restrictive leasehold on which construction is raised; and

(4) where the property has been constructed in stages.

So far as the fourth category is concerned (and these applications are concerned with that) this Court said (at p. 355 of AIR) :-

"The fourth category of premises we must deal with is the category where the premises are constructed in stages. The discussion in the preceding paragraph of this judgment provides an answer to the question as to how the rateable value of this category of premises is to be determined when the premises at the first stage of construction are to be assessed for rateable value, the assessing authorities would first have to determine the standard rent of the premises under sub-sec. (2)(a) or (2)(b) or (1)(A)(2)(b) or (1 )(B)(2)( b) of S. 6 as may be applicable and keeping in mind the upper limit fixed by the standard rent and taking into account the various factors discussed above, the assessing authorities would have to determine the rent which the owner of the premises may reasonably expect to get if the premises are let out to a hypothetical tenant and such rent would represent the rateable value of the premises.

Having said so generally, this Court proceeded to examine the different facets of the question and stated (at pp. 355-56 of AIR) :-

"When any addition is made to the premises at a subsequent stage, three different situations may arise. Firstly. the addition may not be of a distinct and separate unit of occupation but may be merely by way of extension of the existing premises which are self-occupied. In such a case the original premises together with the additional structure would have to be treated as a single unit for the purpose of assessment and its rateable value would have to be determined on the basis of the rent which the owner may reasonably expect to get, if the premises as a whole are let out, subject to the upper limit of the standard rent determinable under the provisions of sub-sec. (l)(A)(2)(b) of S. 6. Secondly, the existing premises before the addition might be tenanted and the addition might be to the tenanted premises so that the additional structure also form part of the same tenancy. Where such is the case, the standard rent would be liable to increase under S. 7 and such increased rent would be the standard rent of the premises as a whole and within the upper limit fixed by such standard rent, the assessing authorities would have to determine the rent which the owner may reasonably expect to get if the premises as a whole are let out as a single unit to a hypothetical tenant and in. such a case, the actual rent received would be a fair measure of the rent which the owner may reasonably expect to receive from such hypothetical tenant unless it is influenced by extra-commercial considerations. Lastly, the addition may be of a distinct and separate unit of occupation and in such a case, the rateable value of the premises would have to be determined on the basis of the formula laid down by as for assessing the rateable value of premises which are partly self-occupied and partly tenanted. The same principles for determining of rateable value would obviously apply in case of subsequent additions to the existing premises. The basic point to be noted in all these cases is - and this is what we have already emphasised earlier - that the formula set out in sub-secs.(l)(A)(2)(b) and (1)(B)(2)(b) of S. 6 cannot be applied for determining the standard rent of an addition, as if