Explanation:

 The hot arid western region of India (19,084 million ha) occurs in the western part of Rajasthan State which contains the dominantly sandy Thar Desert. Based on the climatic, edaphic and terrain characteristics, the region has been further subdivided into three sub-zones: (a) Arid western plain (zone I, 12,416 million ha), (b) Transitional plain of inland drainage (zone II, 3,699
million ha), and (c) Transitional plain of Luni basin (Zone III, 2,969 million ha). The climate of the region being arid, erratic behaviour of the meagre rainfall (100-450 mm/year; ~90% during July-September), extreme temperatures (often >45°C in the peak of summer and sub-zero in winter) and high summer winds (>30 km h-1 during sandstorms in summer) are the perpetual
climatic problems to reckon with, especially for agriculture.