Can I crack the IIT-JEE in 6 months from zero level? If yes,
then how should I approach my preparation?
Yes definitely you can make it into an IITs by studying just for 6
months by following the following detailed way.
You have 6*30 days + 3 days (31st day of alternative months) = 183
days.
70 days for math (Imp chapters)
70 days for physics ( imp chapters)
43 days for chemistry ( it’s a theoretical subject and have less
numericals )
Now,
You got 24 hours in a day.
5 hours for sleeping
5 hours of classes (if any)
3 hours for eating, bathing ( including dinner and breakfast)
11 hours for studies with ful on concentration including 15 minutes
of break every 2 hours ( very easy 
)
Now . You are studying 11 hours a day means 11183 = 2013 hours
( enough)
A person preparing for JEE has to study 5 hours to finish his
syllabus in 12 months.
Yours schedule:- 183 * 11 = 2013 hrs
Above person’s schedule :- 365 * 5 = 1825 hours
Now believe me the above data says that your 6 month course for
JEE is more than a person studying for 5 hours everyday for 12
months
Best of luck…