Consider the following statements: The South-West Monsoon originates in India due to 1. low pressure in the Punjab plain 2. high pressure in areas South of India 3. equatorial low being filled up by descending air current 4. the Himalayas Which of the statements given above are correct?

The South-West Monsoon is primarily driven by the pressure gradient between the Indian subcontinent and the southern Indian Ocean. During summer, intense heating leads to a thermally induced low-pressure area over northwestern India, specifically the Punjab plains and interior Asia [c1][c2][c5]. Simultaneously, a high-pressure cell, known as the Mascarene High, develops south of the equator near the Mascarene Islands [c2][t1]. This pressure differential attracts the southeast trade winds from the southern hemisphere. As these winds cross the equator, the Coriolis force deflects them to the right, causing them to enter the Indian peninsula as south-westerly winds [c4][c5]. While the Himalayas act as a physical barrier that prevents cold Central Asian winds from entering and funnels monsoon moisture, they are not the primary 'origin' mechanism like the pressure gradient [t9]. Statement 3 is incorrect because the equatorial low (ITCZ) is a zone of convergence and rising air, not descending air [t1].

Sources

1. [1] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 4: Climate > Pressure and Winds > p. 28
2. [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > JET STREAM AND INDIAN MONSOON > p. 8
3. [3] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 23: Pressure Systems and Wind System > Monsoons > p. 320
4. [4] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 4: Climate > THE SOUTHWEST MONSOON SEASON > p. 35
5. [5] https://mausam.imd.gov.in/imd_latest/monsoonfaq.pdf