BharatNotes What is Biogeographic Zones of India?
A biogeographic zone is a large geographical region whose climate, landform, soil, vegetation and animal life form a broadly distinct ecological unit. India was divided into 10 such zones by W. A. Rodgers and H. S. Panwar of the Wildlife Institute of India (WII) in their report Planning a Wildlife Protected Area Network in India (1988). Each zone was split into smaller biotic (biogeographic) provinces — 25 provinces in the original 1988 scheme; a later review by Rodgers, Panwar and Mathur (2000/2002) revised the province count. The purpose was practical: to ensure that every distinct ecosystem in India is represented in the network of national parks, sanctuaries and reserves.
The Ten Zones and Their Area
The figures below are the standard percentages of India's total geographical area cited from the WII classification.
| # | Biogeographic Zone | Approx. share of area | Signature feature |
|---|---|---|---|
| 1 | Trans-Himalaya | ~5.6% | Cold desert (Ladakh, Spiti); snow leopard, wild yak |
| 2 | Himalaya | ~6.4% | Altitudinal forest belts; alpine meadows |
| 3 | Indian Desert | ~6.6% | Thar (sandy) and Kutch (saline) deserts |
| 4 | Semi-Arid | ~16.6% | Aravalli belt; transition desert-to-plateau |
| 5 | Western Ghats | ~4% | Tropical evergreen forests; biodiversity hotspot |
| 6 | Deccan Peninsula | ~42% (largest) | Deciduous forests, plateaus |
| 7 | Gangetic Plain | ~10.8% | Alluvial plains; high human density |
| 8 | North-East India | ~5.2% | Transition zone; very high endemism |
| 9 | Coasts | ~2.5% | Beaches, mangroves, estuaries |
| 10 | Islands | ~0.3% (smallest) | Andaman & Nicobar; Lakshadweep |
The Deccan Peninsula is by far the largest zone (~42%), while the Islands zone is the smallest (~0.3%).
Why It Matters
The scheme is the backbone of India's systematic conservation planning. By mapping zones and provinces, WII could identify "gaps" — ecosystems that were under-represented in the existing reserve network — and recommend new protected areas accordingly. It links directly to the design of the biosphere reserve programme (begun 1986) and to tiger-reserve siting under Project Tiger. It also explains India's exceptional richness: the country straddles parts of two of the world's major biogeographic realms (the Palaearctic in the Trans-Himalaya and the Indo-Malayan/Oriental across most of peninsular and north-east India), producing high diversity and endemism.
UPSC Angle
For Prelims, memorise the count (10 zones), the largest (Deccan Peninsula) and smallest (Islands) zones, and unique tags such as Trans-Himalaya being a cold desert. For Mains (GS1 physical geography; GS3 biodiversity/conservation), use the scheme to argue why protected-area planning must be ecology-based rather than administrative, and connect it to biodiversity hotspots and biosphere reserves. Avoid the common error of equating biogeographic zones (ecological) with India's physiographic divisions (relief-based) — they are different frameworks built for different purposes. This is a foundational concept that underpins a wide family of environment questions rather than one specific past question.
