It seems most German consulates in India lifted covid-19-related visa appointment restrictions for language course and exchange students.

So for those of you who already passed TestDaF, you should apply for an appointment in the category "Student Exchange Program". You do not need an "aggregate score 90% in 12th Standard" for that anymore. For those of you who intend to do a course at IIK, please select the category "Language course/internship in preparation for a study (course)".

Here is the link for visa appointments: https://visa.vfsglobal.com/ind/en/deu/book-an-appointment

Select "For National visa application (stay in Schengen is for more than 90 days) submission at the VAC or at the Embassy/Consulate please click here" from there.

Good luck!