Which system was introduced by the British to make the unwilling cultivators produce opium? How did this system work?

The system of advances was introduced by the British to persuade the unwilling cultivators to produce opium.

In the rural areas of Bengal and Bihar, large number of poor peasants never had enough to survive. They faced difficulties in paying rent to the landlord or managing their daily requirements of food and clothing. Through the village headmen, the government’s opium agents advanced money to them. They felt tempted to accept it, hoping to meet their immediate needs and pay back the loan at a later date.