Face-on view of the Galactic region surveyed by SEDIGISM (confined within the dotted lines; top panels) overlaid with spiral arm tracks defined by TC93: the 3 kpc arms in magenta, the Norma-Outer arm in red, the Scutum-Centaurus arm in blue, the Sagittarius-Carina arm in green, and the Perseus arm in yellow (the solid lines merely trace the bottom of the potential, and do not correspond to a real ‘thickness’). The position of the Sun is indicated with a green circle, while the Galactic centre is shown with a green ‘X’. In the top-left panel, coloured dots represent the number density distribution of all molecular clouds identified within the SEDIGISM field by DC21. The top-right and bottom panels show the distribution of the clouds in the full sample with respect to the spiral arms in xy and lv space, respectively. Clouds are colour-encoded by the attributed spiral arm. Objects in the inter-arm region are in cyan and clouds with uncertain allocation are shown in grey. The latter consist of clouds associated with the 3 kpc arms and those with unreliable distances.