Understanding India's Coastal Plains

India has a long coastline stretching along the Bay of Bengal in the east and the Arabian Sea in the west. The landmass adjacent to the sea is known as the coastal plain. These plains are generally formed by the deposition of sediments carried by rivers.

The 'Hexadeltaic Region' Explained

The question asks to identify the specific coastal plain referred to as the 'Hexadeltaic region' or the 'Gift of Six Rivers'. The term 'Hexadeltaic' suggests a region heavily influenced by six river deltas. A delta is a landform created by deposition of sediment that is carried by a river as the flow leaves its mouth and enters slower-moving or standing water.

Identifying the Odisha Coastal Plain

The coastal plain of Odisha, also known as Utkal Plain, is located on the eastern coast of India. It is characterized by its rich alluvial deposits and is formed primarily by the Mahanadi river system.

This specific plain is famously known as the 'Hexadeltaic region' or the 'Gift of Six Rivers' because it is formed by the combined deltas of not just one, but several major rivers draining into the Bay of Bengal. These six rivers traditionally cited are:

• Mahanadi
• Brahmani
• Baitarani
• Subarnarekha
• Rushikulya
• Vamsadhara

The extensive delta formation and the significant contribution of these multiple river systems make this plain a unique geographical feature, earning it the title 'Hexadeltaic region'.

Why Other Options Are Less Suitable

• Coastal plain of Tamil Nadu: While this plain (Coromandel Coast) is formed by rivers like Kaveri, it is not typically referred to by the specific 'Hexadeltaic' title.
• Coastal plain of Karnataka: This is a narrow coastal strip along the Arabian Sea, largely formed by the Western Ghats, and lacks the extensive deltaic features associated with the eastern coast.
• Coastal plain of Andhra Pradesh: This plain, formed by rivers like Godavari and Krishna, is highly deltaic but the specific title 'Hexadeltaic region' or 'Gift of Six Rivers' is predominantly associated with the Odisha plain due to its unique combination of six rivers.

Therefore, the coastal plain of Odisha is the correct identification for the 'Hexadeltaic region' or the 'Gift of Six Rivers'.