Nepali very popular festival dasai tihar

Dasai Tihar is a festival celebrated in Nepal. It seems there might be a slight confusion in your question, as Dasai and Tihar are separate festivals. Dasai, also known as Dashain, is a major Hindu festival celebrated over 15 days, primarily in Nepal. Tihar, on the other hand, is another significant Hindu festival celebrated in Nepal, also known as the festival of lights, usually lasting for five days.

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