Another major, though erratic, export item was indigo dye, which was extracted from natural indigo, and which came to be grown in Bengal and northern Bihar.
After trade routes opened to the east, indigo was imported from India as a substitute for woad, and the cultivation of woad became uneconomical in Europe.
Isatis tinctoria | Indigofera | Roccella tinctoria | Indigofera tinctoria | Indigofera suffruticosa | Genista tinctoria | Alkanna tinctoria | Weinmannia tinctoria | Morinda tinctoria | Maclura tinctoria | Leea tinctoria | Indigofera australis | Gunnera tinctoria | Ficus tinctoria | Chrozophora tinctoria | Baptisia tinctoria |
In Indonesia, the Sundanese use Indigofera tinctoria (known locally as tarum) as dye for batik.