The quality of being absolutely necessary or essential.

अत्यावश्यकता

English Usage: His indispensableness to the team was evident when they struggled without him.

Hindi Usage: जब वे बिना उसके संघर्ष कर रहे थे, तो टीम के लिए उसकी अत्यावश्यकता स्पष्ट थी।