Which one of the following is also called 'Terror of Bengal'?

The correct answer is Option (2) → Water Hyacinth

Option (1) Parthenium — Incorrect. Parthenium is carrot grass.

Option (2) Water Hyacinth — Correct. Of the options, only water hyacinth carries the name ‘Terror of Bengal’. It was brought to India for its flowers and now blocks waterways with its fast growth.

Option (3) Vallisneria — Incorrect. Vallisneria is a water-pollinated plant, not a pest weed.

Option (4) Hydrilla — Incorrect. Hydrilla is a submerged water plant, not called by this name.

Note: This question is from Chapter 16, Environmental Issues, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.

NCERT Extract (Pre-rationalised edition, Chapter 16, Environmental Issues):
Domestic Sewage and Industrial Effluents – “… You may have seen the beautiful mauve-colored flowers found on very appealingly-shaped floating plants in water bodies. These plants which were introduced into India for their lovely flowers have caused havoc by their excessive growth by causing blocks in our waterways. They grow faster than our ability to remove them. These are plants of water hyacinth (Eichhornia crassipes), the world’s most problematic aquatic weed, also called ‘Terror of Bengal’.”