The answer to the crossword question “Indigo plant is ANIL” is referring to the fact that the plant used for producing the popular blue color dye, indigo, is called the anil plant. The anil plant, also known as Indigofera tinctoria, is a flowering plant that produces dark blue leaves and is predominantly found in India and Southeast Asia. The plant has been used for centuries to create a blue dye used in clothing, fabric, and other textiles. The use of anil plant was popularized during the colonial era with the cultivation of the plant and growth of indigo trade. Today, synthetic indigo dye is commonly used, but the anil plant remains an important cultural and historical aspect of textile production in many parts of the world.