Diversity of CO₂ anti-symmetric stretching mode observed fluxes with the Infrared Space Observatory (ISO) and Akari (source B35A) towards various astronomical lines of sight, including many massive protostellar objects. The profiles vary with some showing slightly warped asymmetric shapes (e.g. GL2591, B35A, Elias 29, GL989, HH100 IR, and NGC753 8). A linear baseline passing through continuum points on each side, far from the band centre, indicated by circles, is plotted in each panel to show the various degrees of band asymmetry.