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 thermal contrast between the Indian landmass and the surrounding oceans. During summer, intense heating creates a low-pressure area over northwestern India, specifically the Punjab plain and the Thar Desert [c1][c2][t8]. Simultaneously, a high-pressure cell (Mascarene High) exists over the southern Indian Ocean [c4][t5]. This pressure gradient draws moisture-laden trade winds from the southern hemisphere across the equator, where they deflect right due to the Coriolis force and enter India as south-westerly winds [c1][c2]. Statement 3 is incorrect because the equatorial low (ITCZ) is a zone of rising air (convection), not descending air [t3]. While the Himalayas act as a physical barrier that funnels moisture and prevents cold Central Asian winds from entering, they are not the primary 'origin' mechanism for the monsoon's birth, which is fundamentally pressure-driven [t4].

Sources

1. [1] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 4: Climate > Pressure and Winds > p. 28
2. [2] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 4: Climate > Advancing Monsoon (The Rainy Season) > p. 30
3. [3] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 4: Climate of India > JET STREAM AND INDIAN MONSOON > p. 8
4. [4] https://static.pib.gov.in/WriteReadData/specificdocs/documents/2025/jul/doc2025715586601.pdf
5. [5] https://www.sciencedirect.com/science/article/abs/pii/S0921818125000359