Q. Indigo cultivation in India declined by the beginning of the century because of (UPSC Prelims 2020)
Answer: its unprofitability in the world market because of new inventions
Notes: The correct answer is [B] its unprofitability in the world market because of new inventions. While there was significant local resistance, the primary reason for the systemic decline of natural indigo at the turn of the 20th century was economic obsolescence.

• New Inventions (Statement B – Correct): Towards the end of the 19th century, German chemists developed synthetic indigo (aniline dyes). These synthetic dyes were much cheaper to produce and more consistent in quality than the natural dye extracted from plants. This made Indian natural indigo uncompetitive and led to a collapse in international demand.
• Peasant Resistance (Statement A – Incorrect): Although the Indigo Revolt (1859-60) in Bengal was a massive uprising against the oppressive "tinkathia" system, it led to the shifting of cultivation from Bengal to Bihar (Champaran) rather than a total decline. Resistance was a symptom of the struggle, but the global market shift was the terminal blow.
• National Leaders' Opposition (Statement C – Incorrect): While Mahatma Gandhi led the Champaran Satyagraha in 1917, his movement was aimed at relieving the peasants from the illegal cesses and oppression by planters during the industry's dying days. The industry was already failing due to synthetic dyes by the time the national movement took up the cause.
• Government Control (Statement D – Incorrect): The British government generally supported the interests of the European planters. Although the Indigo Commission (1860) acknowledged the planters' cruelty, the government did not implement controls that led to the industry's decline; rather, it was the "German dye" that dictated its end.

By World War I, the supply of synthetic dyes from Germany was interrupted, briefly reviving natural indigo, but the industry never recovered its former dominance.