Neutral (HI) gas clouds associated with galaxies are responsible for fuelling the star-formation in the universe.

These stars further inject metals back into the neutral gas clouds both within and outside the galaxy.

The circle continues with metals, radiation and dust from stars influencing the neutral to molecular gas (HI-H2) transition

which further influence the next generation of star-formation. Further, gas abundance and kinematics are influenced

by larger factors such as galactic interactions and mergers. 
In my talk, I will focus primarily on my study of high column density neutral gas clouds (Extremely strong Damped Lyman-alpha absorbers, or ESDLAs)

that are observed as absorption signature along the line-of-sight (LOS) of a quasar.

I will further look at the HI-H2 transition and interesting results relevant to diffuse molecular gas.

I will also discuss comparisons between low and high star-forming environment and talk about different samples and techniques

that can be used to study them.