  When a neutral meson $(P^0 \text{ or } \bar P^0)$ decays to two vector
particles, a large number of observables can be constructed from differential
decay rate based on the polarization of final state. But, theoretically, all of
them are not independent to each other and hence, some relations among
observables emerge. These relations have been well studied in the scenario with
no $T$ and $CPT$ violation in neutral meson mixing and no direct $CP$ violation
as well. In this paper, we have studied the relations among observables in the
presence of $T$, $CP$ and $CPT$ violating effects in mixing only. We find that
except four of them, all the other old relations get violated and new relations
appear if $T$ and $CPT$ violations in mixing are present. Invalidity of these
relation will signify the presence of direct violation of $T$, $CP$ and $CPT$
(i.e. violation in the decay itself).
