Complex sentence: In recent years Downderry has suffered terribly from poor planning control, and several unsympathetic buildings have been erected and overdevelopment has occurred due to a unsustainable number of "garden developments".
Split into simpler sentences: In recent years Downderry has suffered terribly from poor planning control. Several unsympathetic buildings have been erected and overdevelopment has occurred due to an unsustainable number of "garden developments".