With reference to India, which one the following statements is not correct?

Statement (1) is not correct. The dominant source of irrigation in India is groundwater (wells and tube-wells): well/tube‑well irrigation expanded rapidly and now constitutes the largest share of irrigated area, having increased many times since the 1950s–60s [2], and groundwater irrigates roughly 62–63% of the irrigated area [3]. Alluvial soil is indeed the predominant soil of the northern plains, supporting intensive agriculture. The assertion about mountain areas being about thirty percent of the country is a conventional broad estimate and does not invalidate the other options. Therefore, among the four statements, the claim that “about one‑third of the area records more than 750 mm annual rainfall” is the incorrect item in this list.

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 12: Major Crops and Cropping Patterns in India > Irrigation Systems > p. 69
2. [2] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 9: Agriculture > Area and Sources of Irrigation (area in thousand hectares) > p. 34
3. [3] https://www.macrothink.org/journal/index.php/ijim/article/download/20399/15847