To understand this you need to understand what led to the revolt of 1857 and how British addressed it.
Many Europeans came and established their trade settelments along the Indian coast. Their motives were purely commercial, which led to Anglo-French rivalary in Carnatic. The French realised it is very easy to defat native powers , but British outmanovoured them to become masters of Bengal after Battle of Pallasey.
After the Battle of Buxar British never looked back and the period from 1757 to 1857, saw rapid British expansions, which curbed the financial resources of the country.British could not concentrate on administration of conquered territories.
After the revolt the following policies were introduced
British said no to expansion
The crown took control of administration (earlier it was under company)
Administrative reforms were introduced to restore law and order.
Indians were admitted into civil services.
Revenue reforms were introduced.
British realised native rulers were essential for thier survival.
This way british bought law and generated employment for Indians, thus they could consolidate their power in India and prevented further mutiny.
