As a tax payer of India, I find it appalling that 25% seats remain vacant after the main rounds of admissions at premier institutes such as NITs, and IIITs, despite being over-demanded! These seats are vacant because candidates casually fill choices and Accept seats and later abandon them. IITs have minimized vacancies by disallowing candidates who Accept an IIT seat from writing JEE (Adv) again. NITs, IIITs, etc. can similarly minimize vacancies by extending this rule to all JoSAA seats. Such a rule, along with other simple measures, would vastly improve the efficiency of utilizing seats, and as a result everyone would be better off. (Despite careful and timely recommendations from an expert committee, JoSAA did not implement these changes in 2018, passing the buck to CSAB's stopgap Special Round. This wastage should definitely not repeat in 2019 onwards!)

Read following articles for more information:
(1) https://www.pressreader.com/india/the-times-of-india-mumbai-edition/20180713/282071982669973
(2) https://medium.com/@ykanoria/why-thousands-of-nit-and-iiit-seats-will-be-wasted-again-in-2018-ed7e48645f61
(3) http://www.columbia.edu/~yk2577/submissionIndian-engg-admissions.pdf