because that's what the definition of Crude on MCX is
Due date rate shall be the settlement price, in Indian rupees, of the New York Mercantile Exchange’s (NYMEX)# Crude Oil (CL) front month contract on the last trading day of the MCX Crude Oil contract.
To delivery settlement of WTI and/or Brent means both producers and consumers has to be on exchange. In Indian market you won't get oil exploration firms. and that's why it's "financial derivative" which derives indian rs prices from WTI Crude from NYMEX.