Which type of fuel is used by PSLV in its operations?

PSLV uses a mix of solid fuels and liquid fuels or propellants at different stages of its flight.You can read about the GSLV Mk III – A Comprehensive Overview of Heavy Lift Launch Vehicle in the given link.

Further readings:

1. Indian Space Research Organisation [ISRO Notes for UPSC]
2. Mars Orbiter Mission (MOM) – A Complete Overview of Mangalyaan Mission