Hi Swapnil,
Triangular Trade serves 2 purposes (as I know):
1. Saves Tax for company
2. A process to pay royalty to holding company.
Example, lets say:
A is the producer in Denmark (A is part of the multinational company)
B is the invoicing company(B is also part of the multinational company) in Switzerland
C is the external customer for the company in India.
C places an order to company B to supply goods. C in turn places order to A to supply the goods directly to customer C.
Now company A delivers goods to C but invoices company B. The tax rates are either low or nil since it is intercompany within EU.
Company B will in turn invoice customer C with a low tax as the applicable tax rates are Swiss.
The company saves on the tax as the rates would have been higher if the customer was invoiced directly from company A.
Anil