"On" is used with projects or tasks to indicate involvement (പങ്കാളിത്തം സൂചിപ്പിക്കാൻ). "In" is used for location or condition (ലൊക്കേഷനോ അവസ്ഥയ്ക്കോ), "with" suggests accompaniment (കൂടേ), and "for" indicates purpose or benefit but not involvement in the project itself.