Hey,

There are ample number of colleges which requires less than 75% in your 12th grade to get admission for btech. Some of them are given below-

Aligarh Muslim University: Aligarh Muslim university conducts a common entrance exam for B.tech admission in AMU.The minimum eligibility for candidates is class 12 with subjects of Physics,Chemistry, Mathematics and English and minimum percentage of 50 percent marks.

Jamia Millia Islamia:  JMIEEE is an entrance test conducted by Jamia Millia Islamia for admission to B.Tech courses. minimum aggregate of 50 percent with PCM subjects are eligible to apply.

SRM UNIVERSITY-  SRM entrance is conducted for admission to B.Tech in SRM university. Students who have passed class 12 with minimum of 70 percent in subjects of Mathematics, Physics and Chemistry are eligible to apply.

VIT- VITEEE is   conducted for B.Tech admission in VIT. minimum aggregate of 60 percent in PCMB subjects are eligible to apply.

Hope this helps.