As a result of being brewed for export to India on slow sailing ships, IPA has a few distinct characteristics. One, it's extremely hopped, resulting in a sharp, dry brew with high bitterness. This is because hops act as a preservative, and were used to ensure the beer survived the long trip Around the Cape. Two, it's a light brew, appropriate for the hotter climate of India and the subcontinent. Three, it is (in modern times) brewed with a handful of oak chips in the vat/carboy during fermentation to simulate the effect of being shipped a month or two in oak hogsheads.