The Sunderbans mangrove forests and tiger reserve are found in the delta of which major Indian river system?

Introduction / Context:
The Sunderbans are one of the most famous mangrove ecosystems in the world and form a key UNESCO World Heritage Site. They are also known for the Bengal tiger and complex network of tidal waterways. This question checks the learner ability to associate the Sunderbans with the correct river delta system in eastern India and Bangladesh.

Given Data / Assumptions:
• Sunderbans refers to a mangrove forest region and tiger reserve. • The area lies in a river delta along the Bay of Bengal. • Options include several river deltas such as Godavari, Ganga, Mahanadi, Krishna and the Luni region. • Standard maps of eastern India are assumed.

Concept / Approach:
The Ganga, after joining with the Brahmaputra and Meghna systems, forms a huge delta at its mouth along the Bay of Bengal. The lower part of this delta, especially in West Bengal and Bangladesh, is covered by dense mangroves known as the Sunderbans. Thus the approach is to identify that Sunderbans belong to the Ganga Brahmaputra delta system, often shortened as Ganga delta in exam questions.

Step-by-Step Solution:
Step 1: Recall that the Sunderbans lie to the south of Kolkata and extend into Bangladesh along the Bay of Bengal. Step 2: This region is formed by distributaries of the Ganga and Brahmaputra, especially the Hooghly and Padma channels. Step 3: Among the options, only the Ganga delta fits this spatial context. Step 4: The Godavari and Krishna deltas lie along the Andhra coast, while the Mahanadi delta lies along the Odisha coast, and Luni does not even form a delta on the sea. Step 5: Therefore, the correct answer is the Ganga delta.

Verification / Alternative check:
Geography textbooks and atlases explicitly label the Sunderbans as a part of the Ganga Brahmaputra delta. Protected area lists describe Sunderbans National Park and Reserve Forest within the lower Ganga delta system. Downstream maps from Kolkata clearly show the mangrove belt in the Ganga delta region.

Why Other Options Are Wrong:
The Luni River: This is an inland river of Rajasthan that flows towards the Rann of Kachchh and does not form a true marine delta. Godavari Delta: Located along the east coast in Andhra Pradesh and known for rice cultivation, not for Sunderbans. Mahanadi Delta: Situated in Odisha, with its own coastal wetlands but distinct from the Sunderbans. Krishna Delta: Another important delta in Andhra Pradesh but not associated with the Sunderbans mangrove forests.

Common Pitfalls:
Students sometimes confuse different east coast deltas and may wrongly pick Godavari or Mahanadi fuels by general knowledge of fertile deltas. Others may forget that Sunderbans straddles India and Bangladesh and is directly tied to the Ganga and Brahmaputra system. Remembering the unique combination of mangroves, tigers and the Ganga Brahmaputra delta helps fix this association.

Final Answer:
The Sunderbans mangrove forests and tiger reserve are found in the Ganga Delta.