[en] Highlights: •MHD activities have been noticed in the microwave interferometer signal. •The role of mode coupling in determining the disruption phenomena in Aditya tokamak has been studied. •Type I discharges with single frequency mode MHD activity, spans for a longer time. •Type I discharge has a single dominant frequency of ∼ 10 kHz. •The type II discharges have MHD activities with more than one dominant frequency and end up in disruptions. -- Abstract: The magnetohydrodynamic (MHD) modes and sawtooth activities are observed in many discharges in 100 GHz interferometer signal in Aditya tokamak. Two types of discharges are observed: one with a single dominant mode and the other with multiple modes during the current flat top of the discharge. Time frequency and the bispectral analysis of these discharges of the interferometer signals allow studies of mode coupling and its role in sustenance and termination of discharges. The role of mode coupling in determining the disruption phenomena in Aditya tokamak discharges using microwave interferometer diagnostics is reported.