Section 19(4)(b) in The Rajasthan Sales Tax Rules, 1995
(b)In the case of a registered dealer not covered by clause (a) above, the return in form ST 5 shall be filed by him for each quarter of the assessment year not later than thirty days, of the end of each quarter, where the tax liability both under the Rajasthan Sales Tax Act, 1994 and the Central Sales Tax Act, 1956 exceeds Rupees twenty thousand in the previous assessment year.