Jo hai sab send kardo, pata nahi kya kaam aajae 😀 .. I've got LE two times by sending documents and forms to Chennai office. Below is what I sent both the times:
Limit Enhancement Form - HDFC (You'll find online)
Printed Letter stating reason for LE (I mentioned I wanted to travel with family in future so needed more limit for huge spending)
Latest 3 months Salary Slips
Latest ITR copy
Latest 3 months bank statement (if your account is not with HDFC)