Solution:
Happy Karwa Chauth" is a special greeting people use during the
Karwa Chauth festival. It's a way to wish someone a happy and blessed Karwa Chauth, which is a Hindu festival where married women fast for their husbands' well-being and longevity. So when you say "Happy Karwa Chauth," you're wishing them a joyful and successful observance of this tradition.