Explanation:

The temperate and cool climate of the Indian hills was seen as an advantage, particularly since the British associated hot weather with epidemics.Cholera and malaria were particularly feared and attempts were made to protect the army from these diseases. The overwhelming presence of the army made these stations a new kind of cantonment in the hills.These hill stations were also developed as sanitariums, i.e., places where soldiers could be sent for rest and recovery from illnesses.
Because the hill stations approximated the cold climates of Europe, they became an attractive destination for the new rulers.It became a practice for viceroys to move to hill stations during the summer months.In 1864 the Viceroy John Lawrence officially moved his council to Simla, setting seal to the practice of shifting capitals during the hot season. Simla also became the official residence of the commander-in-chief of the Indian army.The army's northern command was headquartered in Murree, the Bengal command in Naini Tal,and the southern command in Wellington.