Answer: Contract of collecting land revenue
Notes: Land revenue was the most important source of income for any medieval state. But, its collection was a big challenge for any state. So, different states devised different solutions. One of the solutions was called ijaradari or ijara. Under which, revenue collection was contracted out to private parties, which in turn collected land revenue from local zamindars. These contractors bagged these contracts by promising a lump sum payment to the royal treasury. However, this system was very corrupt. It was much better to directly assess and collect land revenue. E.g. Malik Ambar abolished the old system of giving contracts (ijara) and adopted the Zabtisystem.
