Left panel: HST/WFPC2 F673N image of the central region of NGC 6302. The intensity levels have been chosen to highlight the filament (or “arc”, as depicted by Matsuura et al. 2005), which seems to be the ionised inner rim of the inner ring reported in this work. Middle panel: integrated ¹²CO J = 3−2 emission in the 20 km s^-1 around the systemic velocity of NGC 6302, with a threshold of 0.1 Jy beam^-1. Cyan contours correspond to the emission from V_LSR−40.4 to −30.4 km s^-1 and magenta contours to the emission from −30.4 to −20.4 km s^-1. The first contour corresponds to a level of 1 Jy km s^-1, with a multiplicative step of between adjacent contours. Both rings are apparent in the figure, the main ring running almost vertically, the other inclined, and its major axis running almost along the northwest to southeast direction. Some contours inside the main ring denote a brightness decrease towards holes with no emission (shown in white in the right panel). Right panel: intensity-weighted mean radial velocities in the same intervals as in the middle panel, revealing an expanding kinematics for both structures. The colour-velocity correspondence is shown to the right of the panel. The systemic velocity is V_LSR = −30.4 km s^-1.