I wish to update to macOS Monterey,but i cannot download it due to poor connectivity issue in my area.Are there any alternatives to acess macOS Monterey?

Another option would be to take your MBA into the nearest Apple Genius Bar or Apple Authorized Service Provider and download from there.

OR, your local library. They usually have free WiFi.

Take your MacBook Air to a location with better internet service.

Or if you know someone who has a Mac running Monterey, they can download the Monterey installer for you and install on a Flash drive. Then you can use the flash drive to do your installation.