Indian architecture, throughout the ages, has attracted not only historians, but also architects. This architecture was practiced by ancient sages in the rocky terrain in an environment-friendly manner. None of the regions where rock-cut architecture can be found—namely Egypt, Assyria, Persia and Greece—show as wide a range of imagination as India. Buddhist monks lived and prayed in rock cut cluster of caves for centuries in different geographical regions of India. The built environment of most rock cut caves had adequate daylight, ventilation and hygienic conditions. This letter reveals the principles employed in the design scheme of rock-cut clusters of caves, which were responsible for the establishment of comfortable conditions inside them. Salient features of Buddhist monuments may help the present and future society to learn and implement these aspects and principles where needed.