features to facilitate their identification. The known  regions G353.2+0.9, and G353.1+0.6, the large shell, and a number of other interesting optical structures, like G353.12+0.86 and G353.24+0.64 are indicated in Fig. 2. An elongated structure at RA,Dec.(J2000) = 172430,–3425 (referred to as Structure 1), an optical filament probably linked to WR 93, and the positions of WR93 and Pis24 are also indicated in the figure.

In this paper we investigate the characteristics of the  region G353.2+0.9 and those of the ionized shell G353.12+0.86 and the large shell including Structure 1. The prominent regions G353.1+0.6 and G353.24+0.64 will be analyzed in a subsequent paper.

Figures 3 and 4 show the / and / line ratios. Based on the different excitation conditions, these images provide the evidence to distinguish whether the sources are HII regions, interstellar bubbles or PDRs. Low / and / line ratios are indicative of low excitation conditions associated with  regions such as the large shell; on the other hand, higher / line ratios can be associated with interstellar bubbles. In this context, G353.12+0.86 is a stellar wind bubble.

Figure 5 displays the VLA image at 1.46 GHz, which covers most of the complex. A comparison with the optical images 