Complex sentence: As a scientific organisation, IMU is a member of the International Council of Scientific Union (ICSU), and even though ICMI follows some of the general principles of IMU and ICSU, the organisation has a large degree of autonomy.
Split into simpler sentences: As a scientific organisation, IMU is a member of the International Council for Science (ICSU). Although ICMI follows some of the general principles of IMU and ICSU, the organisation has a large degree of autonomy.