We know that
Purchase from Unregistered Dealer was covered in Reverse Charge in Section 9(4)
Suppose
A sells goods to B
A is Unregistered and B is Registered
In this case,A does not have GST no so he cant charge GST on Invoice
B will deposit this GST directly to Government and then claim Input of Same
Note
When was this Reverse Charge Applicable?
When GST was introduced, this rule was applicable to all business
However exemption was provided for local purchases upto 5000 per day
This Rule was removed from 13.0ct 2017
Rule Reintroduced from 1 Apr 2019
Now, this Rule has again been made applicable but only for builders/promoters in construction business on a Purchase of Cement
Suppose a Builder purchase cement from a shopkeeper and he doesn't charge GST on invoice, Builder has to deposit GST directly to government