Revelation of the descent of GRS 1915+105

The enigmatic micro-quasar GRS $1915+105$ has remained in outburst since its discovery in 1992 till 2018, after which an exponential decrease in the X-ray flux was observed thereby putting an end to its three decades long outburst period. Towards this, we extensively analyze the broadband observations (SXT: $0.5-7$ keV; LAXPC: $3-60$ keV) carried out with AstroSat during the period of $2016-2019$. Model independent analysis suggests that GRS 1915+105 displays various types of variability classes ($\delta$, $\chi$, $\rho$, $\kappa$ \& $\omega$) with possible detection of transition from one class to another class, whereas the decay phase shows the evolution of non-structured class (i.e., $\chi$) with gradual decrease in intensity. The temporal analysis of the source during this period reveals the evolution of Quasi-periodic Oscillation (QPO) frequencies (6 Hz to 1.8 Hz) and total rms (30% to 4%). Broadband spectral analysis suggests that the source spectra are well modeled with multi-colored disk blackbody and thermal Comptonization component. Evolution of spectral parameters (T$_{in}$ $\sim$ $1.85-0.9$ keV, $\Gamma$ $\sim$ 3.8 $-$ 1.6) indicate that the source transits from intermediate states to hard state before decaying to quiescent phase. We explore the disk-jet coupling mechanism during the transitions from hard state $\chi$ to intermediate states (variability classes) and vice-versa based on available radio observations. The implication of our results are discussed in the context of accretion disk dynamics around the black hole source and compare with the previous findings of the `canonical' outbursting sources.