Is the 85% attendance rule of IIT (BHU), Varanasi justified?

No, the 85% attendance rule or in fact any fixed attendance criteria of IIT BHU is not justified. The primary purpose of these rules is to restrict the students from exploring anything and keep them inside the classrooms. 

The main purpose should have been to conduct lively classroom sessions such that students themselves are motivated to attend them rather than forcing it on students. In India, attendance is still considered the major parameter to judge the students' interest in studies and academic growth. This mindset is orthodox and needs to be changed for the better.

As a result of these illogical rules, students are forced to attend classes even if they aren’t interested resulting in a lack of actual passion for education. Students are left with no other choice but to attend the classes against their will and trust me anything that is forced loses its value. 

Foreign universities conduct very dynamic classroom discussions and students are attracted to these classes automatically. India still needs to go a long way and implement better techniques to attract students to classes than forcing it upon them.