According to Indian classical music artist Pandit Buddhadev Dasgupta, the idea of fusion is much more than mere mixing of Indian and Western instruments to produce a sound. This tendency often results in a half baked thing. Fusion can only happen when there is a musical exchange between the two forms. In order to achieve that one must go even deeper into the philosophy of both the musical forms than the technicalities of music. While Indian music is characterized by its melodic element and Western music by its harmonics, the essential idea is to locate the spirit. For in any form, irrespective of a single voice singing or multiple instruments playing, there emerges one predominant tone that is the main spirit of any particular music. One needs to understand that tone before fusing one musical form with another.
An interview with Pandit Buddhadev Dasgupta (in text format).