( 1 ) THE petitioner-Gujarat Gas Co is a Public Limited Company having its registered office at Ahmedabad. In the present matter the petitioner has challenged the order of assessment dated 31. 3. 1999 passed by the Joint Commissioner of Income Tax (Assessment) Special Range-8, Ahmedabad. The Assessing Officer after relying upon the circular No. 549, para 5. 12 dated 31. 10. 1989 issued by the Central Board of Direct Taxes (hereinafter referred to as "cbdt") has held that the petitioners total income is Rs. 2,11,81,620. 00, however, as the assessee has filed return of Rs. 5,13,86,320. 00 he shall have to pay the tax on the returnable income in view of the instructions contained in the aforesaid circular. The petitioner has prayed for writ of certiorari quashing and setting the said assessment order and also prayed for writ of mandamus for refund of Rs. 1,69,80,360. 00 with interest at the rate of 15% p. a. from 1. 4. 99 till the date of refund. FACTS:

( 2 ) IN this case, we are concerned with the assessment year 1996-97. The petitioner has filed return on 30. 11. 1996 showing taxable income of Rs. 5,13,86,320. 00. The return was processed under section 143 (1) (a) of t