Question16: But definition of agent sec 2(5) of cgst act contain any type of agent. How to distinguish ''

Answer As already mentioned, Section 24(vii) requires registration in specific cases. It is applicable when the supply is made by agent or any other person. So the definition of agent is not concerned. This sub-section is applicable not only to agent but to other person also.
But the main requirement is making of supply on behalf of any other person. (Reply dt. 18/4/2018)