Donation Received By Trust and Society From New Members

If it is mandatory it cannot be treated as donation. GST applicable 

The amount paid will be covered under section 15.

The whole amount paid will become the consideration for admission in club/society 

Section 15 of gst act.

All my replies were from the perspective of GST 

In common parlance and even in various judgements the donation is always voluntary. If it is mandatory it will not be donation even if you call it.

GST is a taxation law and as per section 15 if on admission if you are charging fees mandatorily then it will form part of supply and GST will be payable on the whole amount.