The great chaitya halls of western India were not built up from the ground but carved downward and inward into solid basalt cliff faces, a method that required excavation to proceed from the ceiling down, since scaffolding could not be removed and adjusted the way it can in above ground construction, making the process essentially irreversible once begun and any major design error effectively permanent. Despite being carved from solid stone, chaitya hall interiors imitate timber construction in remarkable detail, with ceiling ribs, roof profiles and structural details closely copying wooden buildings that have not themselves survived, suggesting the excavated halls preserve, in translated form, an earlier freestanding wooden architectural tradition that has otherwise vanished entirely from the archaeological record.
The site at Karla, cut in the first century CE, and the earlier group at Bhaja are among the finest surviving examples of the pure early form, while the caves at Ajanta, excavated over a much longer span from roughly the second century BCE into the fifth century CE, combine chaitya halls with a far larger complex of vihara residential caves and, in their later phases, some of the most celebrated Buddhist painting to survive from ancient India. These sites were cut along ancient trade routes through the Western Ghats, and their construction was frequently funded by merchants and guilds engaged in that trade, whose donative inscriptions, carved directly into the rock, remain among the most important sources for understanding who actually paid for and used these spaces.