  Environments play an important role in galaxy formation and evolution,
particularly in regulating the content of neutral gas. However, current HI
surveys have limitations in their depth, which prevents them from adequately
studying low HI content galaxies in high-density regions. In this study, we
address this issue by employing the Five-hundred-meter Aperture Spherical radio
Telescope (FAST) with extensive integration times to complement the relatively
shallow Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) HI survey. This
approach allows us to explore the gas content of dwarf galaxies across various
environments. We observe a positive relationship between HI mass and stellar
mass in dwarf galaxies, with a well-defined upper boundary for HI mass that
holds true in both observations and simulations. Furthermore, we find a
decrease in the HI-to-stellar mass ratio ($\rm M_{\rm HI}/M_*$) as the density
of the environment increases, irrespective of whether it is determined by the
proximity to the nearest group or the projected number density. Comparing our
observations to simulations, we note a steeper slope in the relationship,
indicating a gradual gas-stripping process in the observational data.
Additionally, we find that the scaling relation between the $\rm M_{\rm
HI}/M_*$ and optical properties can be improved by incorporating galaxy
environments.
