One of my client is scrap dealer. He purchased waste paper, M S Scrap, plastic waste, iron scrap, etc. But in GSTR 3B declared only sales and paid tax. But declaring urd purchases in purchase coloumn as URD purchases. Now whether we have to pay RCM on such goods? And for your information URD purchases are in same month and sales are declared in same months. Now Is it the correct procedure or not? If not what is the correct procedure? Please inform. 

Reply-  Provision of section 9(4) of CGST Act, i.e. Reverse charge mechanism in case of purchases made from unregistered person (amount more than Rs. 5000/-) was operative upto 12.10.2017. As per notification No. 38/2017 CT (Rate) dated 13-10-2017, all supplies from unregistered person are exempted without any threshold limit. The subsequent Notifications no. 22/2018-Central Tax (Rate) dated 06-08-2018 has extended the exemption from tax liable under the reverse charge basis under section 9(4) till 30-09 2019. This notification has been rescinded by CBIC

And as per CGST (Amendment ) Act, 2018, provision of section 9(4) has been amended and now Reverse charge is not applicable on specified inward supplies received from Unregistered supplier. 

 In case of sale of   Scrap to any registered person by Central Government, State Government, Union territory or a local authority tax shall be payable by the recipient under reverse charge under notification No.4/2017--Central Tax (Rate)] Dated: June 28, 2017. Otherwies no RCM is payable 

Thus if your client is purchasing from Central Government, State Government, Union territory or a local authority tax shall be payable under RCM and shown accordingly in GSTR-3B in Table-3.1(c) and 4(A)(3) otherwise presentation done by you is correct.