Indian Space Research Organization. It has 32 centres across 23 cities or towns in India.

Centralised Recruitment (ICRB) of the Department of Space and Indian Space Research Organization ISRO will recruit for vacancies at 15 centres across India. Since you have taken BTech, this link may interest you : https://engineering.careers360.com/articles/isro-recruitment

You need to have minimum 65% in all semesters. If you are an Electronics (or study in an electronics related field), then ISRO is the right fit for you.