Raj is worth adopting if you've managed to become the Suzerain of many city-states. +2 bonuses to Science, Culture, Faith, and Gold may not sound like much, but receiving these bonuses from four city-states means a +8 bonus to each yield, which is nothing to sneeze at in the Industrial Era. This holds doubly true when playing as Pericles, or if you've built Kilwa Kisiwani or the Országház for even richer bonuses.
Civilopedia entry Edit
When the British East India Company screwed up royally and the British Royal Army had to step in to put down the Sepoy Mutiny, rule of the sub-continent was transferred to the Crown, in the person of Queen Victoria, who was declared Empress of India in June 1858. The British Raj was divided into two aspects: the regions under direct British control, and those ruled by Indian princes (under British “tutelage” of course) … some 565 princely states in 1947 when British dominion ended. Most of these princely states, while nominally sovereign, were under British control regarding their defense, external affairs, communications, transport, and trade (indeed, most of their exports went to England to pay for all this other stuff).