History Ch - 2 From Trade to Territory (The Company Establishes Power) — Social Studies STD 8 — Question

Subsidiary alliance was introduced by Lord Wellesley under which Indian rulers were not allowed to have their independent armed forces. They were to be protected by the Company. They had to pay for the subsidiary forces that the Company was supposed to maintain for the purpose of protection. 
If the Indian rulers failed to make the payment, then part of their territory was taken away as penalty. Some territories of Awadh and Hyderabad were taken as they failed to pay for the 'subsidiary forces'.