Thanks a lot Kritika for answering my query. What I have gathered from your response is that I will have better chance in the COAP rounds A and B in July. Do you think I should withdraw from my seat in NIT and instead aim for COAP rounds in july and IIT spot rounds, if and when held?

No yogesh don't withdraw your seat from any colleges where you have decent chances ,keep the seat untill you secure a seat in iit and at the same time apply for IIT's COAP rounds .I will mention the link below ,just keep on checking it.I hope you have applied for each iit's individualy on their portal. Also register for COAP and after registering for COAP ,again you have to apply individualy for each iit's and pass their selection criteria.http://coap.iitm.ac.in/   (COAP link)And also check this link to be more clear about your doubts.https://www.youtube.com/channel/UCIFzcfxuSiJqAugpz2UNaIA/videos