Several programmes including master's course are teached in English. Hence, to resume studies German language skills cannot be considered as a prerequisite. But, a good command of German language will expand your advantage on your line of work incase you are willing to working for any of the approx. 700 German multinational companies in India. It is generally advisable to learn (A1 and A2) at least two levels before starting your studies in Germany. If the course is completely in German, then proof of proficiency in German Language is required.
German Language Test for the Admission of Foreign study applicants (DSH)
German as a Foreign Language Test (TestDaF)