At the outset, we must recognise that after all, both NDF and on-shore rates are influenced by the identical set of economic and geo-political developments at home and abroad and there is no a priori reason to believe that the two rates will respond differently to the same set of events, except for the difference in time zone leading to difference in the time the prices capture market action.
That said it is true that trans-national entities with presence in India and abroad can provide a link between the two markets and can be instrumental in arbitraging away any emergent differences between the two markets.