With reference to the Indigo cultivation in India during British rule, consider the following statements:
1. Woad plant which was more easily available in Europe acted as a substitute for Indigo.
2. Indigo import into Britain from India decreased rapidly from the late 18th century onwards.
3. Under Nij system, Indigo was produced on land which was directly controlled by planters.
4. Majority of the land producing indigo was under the Nij system.
Which of the statements given above are correct?