Complex sentence: Cities such as Warsaw, Wrocław and Łódź lack a bypass causing transit traffic to go right through the city center causing frustration among the local population, increased congestion, environmental damage and pollution.
Split into simpler sentences: Cities such as Warsaw, Wrocław and Łódź lack a complete bypass, causing transit traffic to go through the city center. This causes frustration among the local population, increases congestion, environmental damage and pollution.