Rockitch

The PSLV has four stages using solid and liquid propulsion systems alternately. The first stage, one of the largest solid rocket motors

The second stage employs the Vikas engine and carries 41.5 tonnes (40 tonnes till C-5 mission) of liquid propellant – unsymmetrical dimethylhydrazine (UDMH) as fuel and nitrogen tetroxide (N2O4) as oxidiser.
On the PSLV and PSLV-XL, first stage thrust is augmented by six strap-on solid boosters. Four boosters are ground-lit and the remaining two ignite 25 seconds after lau

In case of gslv it is a three stage rocket with the first stage using solid fuel second has liquid fuel with vikas engine. The third and distinguishing feature is the cryogenic engine.