Heatmap showing the overlap of molecular transitions with the H i. Each cell represents the number of molecular lines (E_up < 5000 K) from species such as H₂O, HCN, CH₄, C₂H₂, CO, and CO₂ that fall within ±1 ∆λ of the rest wavelength of a given H i transition. Darker colours indicate a higher number of overlapping molecular features, with H i (13–9) exhibiting the strongest contamination, primarily from CH₄ and H₂O. Based on our analysis, lines such as H i (9–6), H i (10–6), and H i (10–7) do not show significant molecular contamination.