Thermoacoustic instability refers to large amplitude acoustic pressure and heat release rate oscillations of periodic nature that occur due to a positive feedback loop between the hydrodynamic, acoustic, and heat release rate fluctuations in the reaction field of a combustor. All these subsystems directly or indirectly affect each other at different time-space scales during all the states of combustor operation. In this talk, we will discuss the interactions occurring between regions of intense vorticity within the reaction field of a combustor, and the implications of acoustic interactions toward mitigation of thermoacoustic instability. In the first part of the talk, we show that the mean and maximum of vortical interactions exhibit a strong delayed correlation with the acoustic pressure oscillations during the state of thermoacoustic instability. In the second part of this talk, we use the concept of delayed acoustic self-feedback to examine a thermoacoustic system interacting with itself through acoustics. We reveal that applying delayed acoustic self-feedback with optimum feedback parameters completely disrupts the positive feedback loop between hydrodynamic, acoustic, and heat release rate fluctuations present in the combustor during thermoacoustic instability, thus mitigating instability. In the final part, we address the dynamical behaviour arising from two thermoacoustic systems interacting with each other. We study the dynamics of two thermoacoustic systems simultaneously subjected to mutual coupling and asymmetric external forcing through experiments and theoretical modelling.