The petitioner is a company incorporated under the Companies Act engaged in the business of providing cellular mobile telephone services. They are also selling mobile phones/handsets. A question arose as to under which entry of the sales tax tariff, the petitioner has to pay sales tax in respect of mobile phones. The petitioner approached the Board of Revenue. A clarification was issued to the effect that mobile phones fall under entry No.5.17 of Schedule VI to SRO 1728 of 1993, under which goods mentioned in the Schedule are eligible for a reduced rate of tax. Accordingly, the petitioner was paying tax only at 6 per cent as against 10 per cent. The petitioner was collecting sales tax from the customers only at 6 per cent. The 3rd respondent initiated proceedings under Section 19 of the Kerala General Sales Tax Act for reopening the assessment for the assessment year 1997-98, on the ground that the petitioner is liable to pay sales tax at the rate of 10 per cent for mobile phones. Although the petitioner objected to the same, a revised assessment order was passed as Ext.P4. The petitioner is challenging Ext.P4 order in this writ petition.