Complex sentence: After the collapse of the Soviet Union, oil import prices to Ukraine reached world market levels in 1993, however gas import prices and transit fees below European levels for Russian exports to Europe through pipelines in Ukraine were set in bilateral negotiations.
Split into simpler sentences: After the collapse of the Soviet Union, oil import prices to Ukraine reached world market levels in 1993. However, gas import prices and transit fees below European levels for Russian exports to Europe through pipelines in Ukraine were set in bilateral negotiations.