Visit a micro ATMs or go to an AEPS centre near you

The banking mitr would have a PoS (Point of Sale) machine/card machine that will allow you to check balance immediately along with other services

Tell the banking agent that you want to check account balance.

Share your Aadhar Card number and bank name, your name and phone number. The agent will insert it in the machine for you

The banking agent will ask for confirmation, that will be done through a fingerprint or iris (eye) scanner

The banking agent will tell you the account balance or will provide a receipt that will tell you the balance in your account

Ask for closing the transaction in front of you to avoid any sort of fraud.