how can I work as a scientist in ICMR after msc biotechnology . what are the test or exams I should give
There are multiple ways of working with ICMR or many other Top CSIR/DRDO Labs after Masters in Biotechnology. Usually they have vacancies once or twice a year for Both Permanent and Temporary Positions. You must keep track of them, besides having Latest GATE/CSIR-NET Score ready with you. Secondly, many Positions, require a PhD, you may perhaps pursue a PhD from some of the higher technical institutes in India, followed by a career in Research or Academia. Apart from this you have another way through AcSIR, where you pursue your MTech/PhD parallely working with CSIR Labs as Scientist.
Apart from this, you may also appear for the BARC OCES/DGFS Exam, in the Biosciences Discipline followed by a Career as Scientist/Officer in one of the Units under Bhabha Atomic Energy Corporation, Government of India and the Public Research Sector.