Among the following, which one is the least water-efficient crop?

(a) Sugarcane ✓ UPSC's answer
(b) Sunflower
(c) Pearl millet
(d) Red gram

Why the answer is (a)

• Sugarcane is a 12–18 month crop needing roughly 1,500–2,500 mm of water (20,000+ litres per kg of sugar), making it the least water-efficient of the four — option (a).

• Pearl millet (bajra) is a hardy dryland crop maturing on 350–500 mm; red gram (arhar/tur) is a deep-rooted rainfed pulse; sunflower needs moderate water (~600–800 mm).

• Sugarcane's water intensity in Maharashtra and UP is a major driver of groundwater depletion, prompting drip-irrigation mandates.

• Hence option (a).

Why the other options are wrong

(b) Sunflower: Sunflower needs moderate water, far less than sugarcane.
(c) Pearl millet: Pearl millet is among the most water-efficient crops.
(d) Red gram: Red gram is a hardy rainfed pulse.

Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.