  The present state of cosmology is facing a crisis where there is a
fundamental disagreement in measurements of the Hubble constant ($H_{0}$), with
significant tension between the early and late universe methods. Type Ia
supernovae (SNe Ia) are important to measuring $H_{0}$ through the astronomical
distance ladder. However, there remains potential to better standardise SN Ia
light curves by using known dependencies on host galaxy properties after the
standard light curve width and colour corrections have been applied to the peak
SN Ia luminosities. To explore this, we use the 5-year photometrically
identified SNe Ia sample obtained by the Dark Energy Survey, along with host
galaxy spectra obtained by the Australian Dark Energy Survey. Using host galaxy
spectroscopy, we find a significant trend with the equivalent width (EW) of the
[OII] $\lambda\lambda$ 3727, 29 doublet, a proxy for specific star formation
rate, and Hubble residuals. We find that the correlation with [OII] EW is a
powerful alternative to the commonly used mass step after initial light curve
corrections. We applied our [OII] EW correction to a sample of 20 SN Ia hosted
by calibrator galaxies observed using WiFeS, and examined the impact on both
the SN Ia absolute magnitude and $H_{0}$. We then explored different [OII] EW
corrections and found $H_{0}$ values ranging between $72.80$ to
$73.28~\mathrm{km} \mathrm{s}^{-1} \mathrm{Mpc}^{-1}$. Notably, even after
using an additional [OII] EW correction, the impact of host galaxy properties
in standardising SNe Ia appears limited in reducing the current tension
($\sim$5$\sigma$) with the Cosmic Microwave Background result for $H_{0}$.
