How do I know if there are any other player in my city?

If there aren't any portals in your area, then no-one will have been able to play, so you might need to create some. See this article on how to do this.

Check Google+ for communities of fellow players in your area, this is how many people team up to collaborate on portals.

At this early stage in the game it may well be that there simply aren't any players - so talk to your friends, see if any of them are interested, and get them to sign up :)

In the intel map if you check the "Restrict to map" at the bottom of the site in the "COMM" box and move the map over to an area (ie Dhaka, Bangladesh in your case) you will see in the "COMM" box all the nearby activity