Hi DanishYes

 it is necessary to qualify jee mains for jee advance.

There is no process for getting admission in IIT without qualifing jee mains and advance.

You need to get rank below 2,45,000 in jee mains to sit in jee advance and in jee advance you need to in under10,000 for admission in IIT

Hope my answer helped you

Thank you

Hi Danish 

Any student can take JEE mains exam if he/she meets the eligibilty criteria and out of that only the top students are eligible to give the JEE advance exam. In 2018, 224000 students cleared the JEE mains. 

Without JEE it is not possible to get into IITs. 

Hello Danish, 

Yes,  it is absolutely necessary to qualify JEE MAINS to be able to sit for JEE ADVANCED. Every year few lakh students sit for the MAINS but only a few thousand qualify for JEE ADVANCED. All NIT colleges and IIT colleges conduct admission on the basis of JEE exams. Therefore you have to qualify JEE ADVANCED to be able to enroll in any IIT. 

Hope this helps :)