CS 2–1 intensities towards G1.6 integrated from 25 to 112 km s⁻¹ (low-velocity component) towards G1.6 are shown in colour-scale and from 112 to 240 km s⁻¹ (high-velocity component) are shown with black contours. Contour levels are 8σ, 12σ, and then increase by 12σ with σ = 1.0 K km s⁻¹. The HPBW is shown in the bottom left corner. The black arrow labelled D2 indicates the position axis along which the PV diagram in Fig. 7 was taken. Black crosses labelled P1–P3 indicate positions selected for further analysis.