The black cotton soil of India has been formed due to the weathering of
Answer & explanation
Answer: (b) fissure volcanic rock
Black cotton soil (regur) forms from the weathering of the basalt lava that poured out of fissures to make the Deccan Traps, so the parent rock is fissure volcanic rock.
- ✓ (b) NCERT calls black soil typical of the Deccan trap (basalt) region and says it is made up of lava flows. The Deccan Traps are a flood basalt province built by lava outpourings through cracks in the crust.
- ✗ (c) Granite and schist are crystalline rocks; NCERT links red soil, not black soil, with crystalline igneous rocks on the Deccan plateau.
- ✗ (a) Brown forest soil is itself a soil, not a rock, so it cannot be the rock whose weathering produces black soil.
- ✗ (d) Shale and limestone are sedimentary rocks; black soil forms from volcanic basalt.
Remember · Black (regur) soil comes from Deccan Trap basalt, which erupted from fissures; it holds moisture well and suits cotton.
📘 Read it in NCERT: Class 10 Contemporary India – II, Ch 1 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 3 (practise this chapter) · Class 10 Contemporary India – II, Ch 1 (practise this chapter)
Sources
- NCERT Class 10 · Contemporary India – II, Chapter 1 “This type of soil is typical of the Deccan trap (Basalt) region spread over northwest Deccan plateau and is made up of lava flows.”
- NCERT Class 11 · Fundamentals of Physical Geography, Chapter 3 “The Deccan Traps from India, presently covering most of the Maharashtra plateau, are a much larger flood basalt province.”
- NCERT Class 10 · Contemporary India – II, Chapter 1 “Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan plateau.”
Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·