Indian Defence Force
It was divided into British and Indian sections. Like the Indian Army of the time, units in the Indian section consisted primarily of British officers and Indian other ranks. Units in the British section were all British. The Indians were volunteers, but many of the Europeans were conscripted, as the Indian Defence Force Act 1917 made military service compulsory for all Europeans permanently residing in British India (including the princely states) between the ages of 16 and 50. Boys between 16 and 18 were only obliged to undertake training and men over 40 only had to serve in their local district, but men between 19 and 40 were obliged to serve anywhere required within the country. Only clergy were exempt.