Costumes worn on the people that celebrate Diwali?

i would imagine they would wear a sari !

Being a Hindu, I wear traditional Dresses on Diwali...

The adults usually wear Sari's but the children wear varied dresses that might include jeans also. Salwar suits or chudidar pajama and kurta are usually worn. Lehangas that pretty much look like sari's are also worn..