Afaik, airtel has changed the login password for routers. Try using your account number as password and username as admin. Else, you'll have to call cc, or you could reset the router(that'll change the password back to password).
When you are connected to Internet
check your IP Current IP Check say Example; 126.96.36.199
retype it in browser addres bar. a new window may appear .
try admin admin or password
some modems work
ID support PW support or password.