Why Correct: Durgapur Steel Plant in West Bengal, established in 1959 with UK collaboration and now under SAIL, earned the nickname "Ruhr of India" due to its industrial concentration and importance, similar to Germany's Ruhr region.
Distractor Analysis: Bhilai Steel Plant in Chhattisgarh is India's first and largest integrated steel plant. Rourkela Steel Plant in Odisha was India's first public sector steel plant. Jamshedpur's Tata Steel is India's oldest and first privately-owned integrated steel plant.
Takeaway: The "Ruhr of India" nickname specifically references Durgapur's industrial belt in West Bengal's Bardhaman district, not other major steel plants.