The interstellar medium (ISM) consists primarily of gas and dust. While dust makes up only 1% of the total mass of the ISM, it plays a decisive role in the physical processes that regulate galaxy evolution. Despite its importance, we still do not understand how the global dust properties depend on metallicity. Most ISM dust is produced and ejected by asymptotic giant branch stars (AGBs) and are easily observed during the Planetary Nebula phase of stellar evolution. Studies of such objects in irregular galaxies of the Local Group have revealed a diverse spectral zoo and proved that low metallicity favours carbon-rich dust production by AGB stars. Tracing the dust evolution with metallicity of carbon stars in these irregular galaxies is, however, not optimal because of their complex star forming histories. With its metallicity gradient, the Milky Way is an ideal laboratory for such studies. In this poster we present an infrared spectroscopic study of the dust of a sample of PNe in the metal poor Galactic anti-centre.