Answer:
Yes.
Step-by-step explanation:
Law of relativity in relation to light states that the speed of light in a vacuum does not depend on all the motion of the observers and that all motion must be defined relative to a frame of reference and that space and time are relative, rather than absolute concepts. This was formulated by Albert Einstein in 1905.
Light travels more slowly in gas than in air because it interacts with atoms of glass that made it way through it and the refractive index of glass is more than air. This does contradict the theory of relativity as the speed of lights travel slower in glass because it's motion is slow and it is not relative.