The government controls all the pipes. They can shut down the backbone connections between the country and its neighbors. Sure, maybe you can catch the neighboring country’s mobile signal at the border, and maybe someone has a satellite uplink, but most of the traffic can be shut down.
Remember, the Belarussian dictatorship has been in place since 1994 – predating the spread of the Internet in the country. The networks in the country were built under the dictatorship’s oversight to begin with.
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