of these two cloud components. The filament “fs1" and a previously known object W33 B are seen toward the overlapping areas of the clouds, where ongoing SF activity is evident. A scenario concerning the converging/colliding flows from two different velocity components appears to explain well the observed signposts of SF activities in the system.'
date:  
title: Uncovering distinct environments in an extended physical system around the W33 complex
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dust, extinction – HII regions – ISM: clouds – ISM: individual object (W33) – stars: formation – stars: pre–main sequence

Introduction {#sec:intro}
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Over the past two decades, due to the availability of various large-scale multi-wavelength surveys, the research concerning the understanding of the formation processes of massive OB stars ($\gtrsim$ 8 M$_{\odot}$) and young stellar clusters has received immense interest, and is being debated [@zinnecker07; @tan14]. In this context, Galactic star-forming sites hosting mid-infrared (MIR) bubbles/shells associated with H[ii]{} regions and/or infrared dark clouds (IRDCs)/elongated filamentary features are thought to be prime targets for exploring the highlighted research problem [e.g., @churchwell06; @churchwell07; @andre10; @andre14]. The exploration of the existing multi-wavelength surveys allows to examine the physical conditions and the kinematics of embedded structures on large-scale areas of these 