  We present the results obtained from the spectral studies of black hole X-ray
binary GX~339--4 using \astrosat~ observations during its 2021 outburst.
\astrosat~ observed the source in the intermediate state for $\sim600$ ks. The
combined spectra of SXT and LAXPC in the $0.7-25$ keV energy range are studied
with phenomenological and physical models. The spectral study reveals a
receding disc and a contracting corona during the observation period. The
outflow rate is found to be increased though the accretion rates did not vary
during the observation period. The X-ray flux decreases as the disc recedes and
the spectrum becomes hard. At the same time, the Comptonized flux decreases
with increasing fraction of thermal emission. This could be plausible that
episodic jet ejection modified the corona and reduced Comptonized flux. An iron
emission line at 6.4 keV is observed in the spectra of all the orbits of
observation. We find that the equivalent width of the iron emission line
correlates with the photon index, indicating a decrease in the reflection
strength as the spectrum becomes hard. We observe that the disc flux does not
follow $F_{\rm DBB}-T^{4}$ relation.
