Scientists with an appreciation for Indian food have been beavering away to explain its appeal (other than the obvious, “It tastes so darn good.”) 
But no, that’s too simple for scientists. There has to be an objective reason.
Their explanation: Western food is based on pairings of similar flavours; Indian food, by contrast, is based on pairings of dissimilar flavours, as shown by various Venn diagrams of flavours found in Indian recipes.
An article in the Washington Post summarises their research: Scientists have figured out what makes Indian food so delicious