Consider the following statements : I. Tides are of great help in navigation and fishing. II. High tide enables big ships to enter or leave the harbour safely. III. Tide prevents siltation in the harbours. IV. Kandla and Diamond Harbour are tidal ports. Which of these statements are correct ?

All four statements are correct. Tides are predictable and therefore help navigators and fishermen to plan operations; tidal flows significantly aid navigation along coasts and estuaries [1]. High tides raise water levels and allow ships to cross shallow bars at harbour entrances, enabling safe entry and exit for large vessels [2]. Tidal flushing — the regular in-and-out movement of tide waters — helps carry sediment seaward and mitigates siltation in estuarine harbours, reducing dredging needs. Finally, Kandla (Deendayal) and Diamond Harbour are explicitly listed as major tidal ports of India, confirming statement IV [3]. Hence option 4 (I, II, III and IV) is correct.

Sources

1. [1] FUNDAMENTALS OF PHYSICAL GEOGRAPHY, Geography Class XI (NCERT 2025 ed.) > Chapter 13: Movements of Ocean Water > Importance of Tides > p. 110
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 32: Ocean Movements Ocean Currents And Tides > Navigation > p. 506
3. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 32: Ocean Movements Ocean Currents And Tides > Explanation: > p. 508