Which one of the following is used in preparing a natural mosquito repellent?
- (a) Congress grass
- (b) Elephant grass
- (c) Lemongrass ✓ UPSC's answer
- (d) Nut grass
Why the answer is (c)
• Lemongrass (Cymbopogon) yields citronella-type essential oils rich in citral and geraniol, which mosquitoes avoid; it is the base of natural repellent sprays, candles and coils — option (c).
• Congress grass (Parthenium) is an invasive weed causing allergies, not a repellent (a).
• Elephant grass (Napier) is a fodder crop (b); nut grass (Cyperus rotundus) is a persistent weed used in some traditional medicines, not as a repellent (d).
• Hence option (c).
Why the other options are wrong
- (a) Congress grass
- Parthenium is an allergenic invasive weed, not a repellent.
- (b) Elephant grass
- Napier grass is fodder, not a repellent.
- (d) Nut grass
- Nut grass is a weed, not a mosquito repellent.
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.