What is difference between plsv and glsv?
Do you mean PSLV and GSLV? If yes than:
PSLV is Polar Satellite Launching Vehicle developed by ISRO to launch Indian Remote Sensing (IRS) Satellite into sun-synchronous orbit. The It is a four stage Vehicle, using solid and liquid propulsion systems alternately
GSLV is Geosynchronous Satellite Launching Vehicle developed by ISRO to launch Indian Geosynchronous Satellite. It is a three-stage vehicle with solid, liquid and cryogenic stages respectively.