Complex sentence: As early as 1974, environmental groups from all the member states established a central representation in Brussels, founding of the European Environmental Bureau, while other environmental NGOs only set up shop in Brussels from the late 1980s onwards.
Split into simpler sentences: As early as 1974, environmental groups from all the member states established a central representation in Brussels, founding the European Environmental Bureau. Other environmental NGOs only set up shop in Brussels from the late 1980s onwards.