The date is commonly given as the fifth to seventh centuries and is not the difficulty. The region is: the Chitrasutra is the earliest surviving Indian treatise on painting, so where it was written bears directly on which surviving wall paintings its rules were written for or against, and the atlas records the region as not established rather than assigning one.
What would resolve this A regional attribution argued from the text itself, from its language, its named places, its ritual assumptions or its relationship to a datable local recension, rather than inferred backward from whichever painting tradition a reader wishes to connect it to.
OpenIndology, Sanskrit textual criticism, history of Indian artDivinity Atlas Open Questions Register, First Edition