Hello aspirant!

No it's not mandatory to qualify both papers of the JEE ADVANCED 2019.However your combined score including paper 1and 2 should be more than or equal to the cut off marks and your scores in individual subjects i.e.subject cut off should be more than or equal to 10 percent.

It depends on the overall cut off of the paper ,which decides the subject cut off marks.So subject cut off individually and overall cut off matters to be eligible for selection into IITS also you must have a good CRL(Common rank list).

Hope it helped!

All the best!