Step 1: Understanding the Concept:
The question asks to identify the longest of the designated National Waterways in India.
Step 2: Detailed Explanation:
National Waterway-1 (NW-1) is the longest National Waterway in India.
\[\begin{array}{rl} \bullet & \text{Route: It stretches from Prayagraj (Allahabad) in Uttar Pradesh to Haldia in West Bengal.} \\ \bullet & \text{River System: It runs along the Ganga-Bhagirathi-Hooghly river system.} \\ \bullet & \text{Length: The total length of NW-1 is 1620 kilometers.} \\ \end{array}\]
The other major waterways, such as NW-2 (on the Brahmaputra) and NW-3 (on the West Coast Canal), are significantly shorter.
Step 3: Final Answer:
National Waterway-1 is the longest National Waterway in India.
Describe any five features of extensive commercial grain farming in the world.