Metals and dust in the neutral ISM: the Galaxy, Magellanic Clouds, and
  damped Lyman-{\alpha} absorbers
  Context. The presence of dust in the neutral interstellar medium (ISM)
dramatically changes the metal abundances that we measure. Understanding the
metal content in the neutral ISM, and a direct comparison between different
environments, has been hampered to date because of the degeneracy to the
observed ISM abundances caused by the effects of metallicity, the presence of
dust, and nucleosynthesis. Aims. We study the metal and dust content in the
neutral ISM consistently in different environments, and assess the universality
of recently discovered sequences of relative abundances. We also intend to
assess the validity of [Zn/Fe] as a tracer of dust in the ISM. This has
recently been cast into doubt based on observations of stellar abundances, and
needs to be addressed before we can safely use it to study the ISM. Methods. In
this letter we present a simple comparison of relative abundances observed in
the neutral ISM in the Galaxy, the Magellanic Clouds, and damped Lyman-{\alpha}
Absorbers (DLAs). The main novelty in this comparison is the inclusion of the
Magellanic Clouds. Results. The same sequences of relative abundances are valid
for the Galaxy, Magellanic Clouds, and DLAs. These sequences are driven by the
presence of dust in the ISM and seem 'universal'. Conclusions. The metal and
dust properties in the neutral ISM appear to follow a similar behaviour in
different environments. This suggests that a dominant fraction of the dust
budget is built up from grain growth in the ISM depending of the physical
conditions and regardless of the star formation history of the system. In
addition, the DLA gas behaves like the neutral ISM, at least from a chemical
point of view. Finally, despite the deviations in [Zn/Fe] observed in stellar
abundances, [Zn/Fe] is a robust dust tracer in the ISM of different
environments, from the Galaxy to DLAs.
