What color & style of kurta would go with a multi colored dupatta?

I am not familiar with Indian clothing styles. However a multi color dupatta (shawl, scarf) would work best with a simple style, solid color outfit (kurta) that is a color in the multi color dupatta. For example if your dupatta is red, yellow, blue & green, a kurta in one of those colors would look good.

A kurta (or sometimes kurti, for women) is a loose collarless shirt worn in many regions of South Asia, and now also worn around the world. (Wiki)

A dupatta a length of material worn as a scarf or head covering, typically with a salwar, by women from South Asia.

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