about RCM

Govt has prescribes supplies on which Recepient is liable to pay GST .

As per defination under section 2 CGST Act
98] "reverse charge" means the liability to pay tax by the recipient of supply of goods or services or both instead of the supplier of such goods or services or both under sub-section [3] or sub-section [4] of Section 9, or under sub-section [3] or subsection [4] of Section 5 of the Integrated Goods and Services Tax Act;

Note : Inward Supplies from URD , section 9(3) is deferred to 30/9/17

Reverse Charge Mechanism is Deferred till 30/9/18

Provision  of section 9(4)- liability of GST under reverse charge on inward supply from unregistered has only been deffered till 30th Sep 2018.
but Services covered under section 9(3) ie GTA, Advocate Services when avail , the RCM has to be done .