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Contact your Internet Service Provider (ISP) or operator
Maybe the reason why your Internet connection is slow is the ISP/Operator itself, due to technical difficulties they are not aware of. Contact them and let them know about this issue and they will instruct you on how to troubleshoot slow internet connection, and resolve the issue by yourself, if possible.
If you only have a limited bandwith (= internet speed), optimize the browser to get the most out of it.
Opera is a web-browser which offers a solution called Opera turbo, which boosts the Internet speed.
Install it and before you start browsing, check if the option Opera turbo is activated (It usually activates itself automatically, when it detects slow internet connection). Find the Opera Turbo icon, on the lower left side of the status bar and click on it.