Your web page is the file index.html in the directory public_html in your home folder on the server math.iisc.ac.in, i.e., for example /home/mickeymouse/public_html
NOTE: For your web page to be seen, you must set permissions for it to be readable (see below for how to do this).
ssh into your mathematics account. (See this page for details.) create a folder called public_html and give it the correct permissions.
mkdir public_html
chmod go+rX public_html
Create your webpage (i.e., file named index.html) locally, i.e., on your PC and upload all the files (including index.html which will be your main page) to the public_html folder on math using an sftp client such as psftp.