CDS (I) 2024 General Knowledge · Question 42 of 120

Correct — A, Nilgiri. The Nilgiri Biosphere Reserve straddles the tri-junction of Tamil Nadu, Kerala and Karnataka in the Western Ghats — three States, which is exactly what the stem asks for. It was notified in September 1986 as India's first biosphere reserve and was added to UNESCO's World Network of Biosphere Reserves in 2000. Its protected areas sit in all three States: Mudumalai, Mukurthi and Sathyamangalam in Tamil Nadu; Bandipur and Nagarhole in Karnataka; and Silent Valley, Wayanad, Aralam and Karimpuzha in Kerala.

• (b)Achanakmar-Amarkantak — Spreads over two States, Madhya Pradesh and Chhattisgarh, along the Maikal range of the Satpuras. Two is not three.
• (c)Seshachalam — Lies wholly inside Andhra Pradesh, in the Eastern Ghats around Tirupati. It is a single-State reserve, best known for red sanders and the slender loris.
• (d)Agasthyamalai — Spans Kerala and Tamil Nadu at the southern tip of the Western Ghats — Neyyar, Peppara and Shendurney Wildlife Sanctuaries plus the Kalakad-Mundanthurai Tiger Reserve. Again two States, not three.

A biosphere reserve is a UNESCO Man and the Biosphere designation for a large area zoned into a strictly protected core, a buffer where research and controlled use are allowed, and a transition zone where people live and work. India has 18 of them, and a reserve is drawn on ecological rather than administrative lines, which is why several of them cut across State boundaries. The Nilgiri reserve was the first India notified, in September 1986, and covers roughly 5,500 sq km of the Western Ghats where Tamil Nadu, Kerala and Karnataka meet.

This item rewards knowing State counts, not names. The quick route is to place each reserve on the map and count boundaries: Nilgiri sits on a three-State junction, Agasthyamalai and Achanakmar-Amarkantak each straddle exactly one boundary, and Seshachalam is comfortably inside one State. Agasthyamalai is the designed trap, because candidates remember it as a multi-State reserve and stop counting at 'more than one'. A second useful anchor is that the Nilgiri reserve contains the Nilgiri Biosphere landscape that holds the largest wild Asian elephant population in the country, spread across all three States.

• The Nilgiri Biosphere Reserve spreads across Tamil Nadu, Karnataka and Kerala.
• Notified in September 1986, it was India's first biosphere reserve; UNESCO added it to the World Network in 2000.
• Its constituent protected areas include Mudumalai, Mukurthi, Sathyamangalam, Bandipur, Nagarhole, Silent Valley, Wayanad, Aralam and Karimpuzha.
• Agasthyamalai spans Kerala and Tamil Nadu; Achanakmar-Amarkantak spans Madhya Pradesh and Chhattisgarh; Seshachalam is entirely within Andhra Pradesh.

• Stopping at 'more than one State' and picking Agasthyamalai, which spans two, not three.
• Assuming every biosphere reserve is on UNESCO's World Network — only 13 of India's 18 are.
• Confusing the biosphere reserve with the Nilgiri district or the Nilgiri Tahr's range; the reserve is much larger than either.

Asked as a one-line 'which reserve spans three States' recall item — CDS put the identical question again in the 2025-I paper.

• practice — not a real PYQ

  The Achanakmar-Amarkantak Biosphere Reserve lies in which two States?

  • (a)Madhya Pradesh and Chhattisgarh
  • (b)Odisha and Jharkhand
  • (c)Maharashtra and Telangana
  • (d)Chhattisgarh and Odisha

  Answer(a) Madhya Pradesh and Chhattisgarh — it lies along the Maikal range of the Satpuras, near the source of the Narmada at Amarkantak.

• practice — not a real PYQ

  Which one of the following biosphere reserves is located entirely within Andhra Pradesh?

  • (a)Agasthyamalai
  • (b)Nilgiri
  • (c)Seshachalam
  • (d)Nokrek

  Answer(c) Seshachalam — in the Eastern Ghats around Tirupati, known for red sanders; Nokrek is in Meghalaya.