Hi Aspirant,

Even if you have already passed class 12th with PCB, you still stand a chance if you want to pursue engineering. You can do so by giving Mathematics paper exam through National Institute of Open Schooling (NIOS). The NIOS is a national board that administers examinations for Secondary and Senior Secondary examinations similar to the CBSE and the CISCE. So through this you can add Mathematics subject required in eligibility criteria to appear for entrance exams of Engineering colleges or study in IITs.

For more information on NIOS refer the link below,

https://school.careers360.com/exams/nios-class-12

Also you can refer the link below for some engineering entrance exams,

https://engineering.careers360.com/articles/top-engineering-entrance-exams-in-india

Hope this is helpful.

All the best!!