Measuring the mass and distance of a gravitational wave (GW) source is a fundamental problem in GW astronomy. It relies on accurate waveform templates. The current templates are developed assuming that the sources are residing in a vacuum, but astrophysical models predict that the sources could form in gaseous environments, move with relatively large velocity, or reside in the vicinity of supermassive black holes. In this talk, I will demonstrate how the above environmental factors could distort the GW signal and lead to an incorrect estimation of the physical parameters. These effects, if not appropriately accounted for in the GW data analysis, may alter our understanding of the formation, evolution, and detection of compact objects and black holes.