Step 1: Recalling the Text:
The 'Indigo' chapter explains that instead of cash rent, tenant farmers were bound by agreement to devote a fixed fraction of their land to indigo cultivation.
Step 2: Explaining Why:
This let British planters secure a steady, nearly free supply of indigo for the dye trade, exploiting the peasants' dependence on their land.
Final Answer:
Peasants were obligated to cultivate indigo on 3/20th of their landholding and surrender it to the landlords as rent, a system landlords enforced purely to profit from the lucrative indigo trade at the peasants' expense.