2025 · Q10
In medieval India, the process of indigo extraction underwent great improvement as a result of the:
General KnowledgeHistory of India
- Ause of fertiliser enhancing the quality of indigo crop.
- Bintroduction of mechanical crushing tools for indigo stems.
- Cuse of gypsum and lime mortars in making the inner surfaces of indigo vats waterproof.
- Demployment of slave labour in quick distilling of indigo curcibles.
Explanation
As shown by Irfan Habib's studies of medieval Indian technology, indigo extraction improved when vats were made waterproof with gypsum-and-lime mortar, allowing the indigo solution to be properly steeped and beaten. The use of fertilisers, mechanical crushers or slave labour was not the decisive improvement; waterproofing the vats was. This waterproofing, combined with the beating (trampling) of the steeped solution, gave a higher and more consistent yield of dye.