D.P. Wadhwa, C.J.

In this batch of writ applications there is challenge to the validity of Bihar Stamp (Prevention of Under Valuation of Instruments) Rules, 1995 framed under Section 47A of the Indian Stamp Act, as amended by Bihar amendment in the year 1988. It is contended that these Rules are in violation of Section 47A of the Act and thus invalid.

2. In some of the writ applications the petitioners are prospective vendors and in some both prospective vendors and vendees. In only one case, documents were presented for registration. In that case there are five petitioners and in case of the first petitioner, the document was accepted for registration and then impounded. Other petitioners claim that their documents were refused even to be accepted.

3. During the pendency of these writ applications the Rules came to be amended inasmuch as in certain rules instead of the words "District Collector" the words "District Sub-Registrar" were substituted. Even then the challenge to the Rules did not cease. For the purpose of the decision of these writ applications we will consider the Rules as amended by the amendment notified on August 21, 1996.

4. In order to understand the rival contentions we may set out the relevant provisions. Section 47A of the Act, in relevant part, reads as under:-

1. Where the registering officer appointed under the Indian Registration Act, 1908 (XVI of 1908) while registering any instrument of conveyance, exchange, gift, partition or settlement has reason to believe that the market value of the property which is the subject matter of such instrument has not been rightly set forth in the instrument (or is less than even the minimum value determined in accordance with any rules made under this Act) he may at the time of admitting such instrument refer the matter to the Collector for determination of the market value of such property and the proper duty payable thereon.

2. On receipt of a reference under sub-section (1) the Collector shall, after giving one month's time to the parties for making their representation and after holding an enquiry determine the market value of the property which is the subject matter of such instrument and the duty as aforesaid. The difference, if any, in the amount of duty, shall be payable by the person liable to pay the duty:

Provided that no such person shall be required to pay any amount to make up the difference if the difference between the consideration or the market value as set forth in the instrument (or is less than even the minimum value determined in accordance with any rules made under this Act) and the market value determined by the Collector does not exceed 10 percent of the market value so determined.

5. For the purpose of this Act, market value of any property shall be estimated to be the price which in the opinion of the Collector or the appellate authority, as the case may be such property would have fetched or would fetch, if sold, in the open market on the date of execution of the instrument of conveyance, exchange, gift, partition or settlement.

5. "Rules with which we will be concerned are-

"5. Guidelines Register of Minimum Value. - For the purpose of assisting the registering officer in finding out actual market value of properties (as accurately as may be possible, the District Sub-Registrar, within the area of the district, shall after classifying the lands of rural or urban areas, prepare a register showing estimated minimum value of the land/properties of that category as per procedure laid down in rule 6.

6. Procedure for the Fixation of Estimated Minimum value. - (1) The District Sub-Registrar shall obtain from the concerned Registering Office the figure relating to the five conveyances of highest value of each category of land/property situated within each Halka of every revenue circle and ward of notified area/Municipality/Corporation that have been registered/presented for registration in the preceding financial year.

(2) The average value of conv