Thus, to defend it and to prevent possible social destabilization, in 1896 (when the eastern and western parts of the Trans-Siberian did not close up yet), the government introduced Chelyabinsk tariff break ()—a tariff barrier for grain in Chelyabinsk, and a similar barrier in Manchuria. This measure changed the form of cereal product export: mills emerged in Altai, Novosibirsk, and Tomsk; many farms switched to butter production. From 1896 to 1913 Siberia on average exported 30.6 million poods (~500,000 tonnes) of cereal products (grain, flour) annually.