Feather

I'd guess peacock secondary wing feather- proportions look about right and the markings(specifically, the lack thereof) are right for a feather in that placement. See this link- https://www.featherbase.info/en/species/pavo/cristatus

Hi Sukanya, from this picture it is difficult to identify, but if you could give some idea of the colour - it looks black with some white, but that may just be the effect of lighting. Also an idea of size would help to narrow it down. Length and width of each side would help. This looks like a wing feather where one side is wider than the other and both have a slight curl in opposite directions to give it an aerodynamic profile.