Complex sentence: The speedy conclusion was only possible because the objectives set by the Mitro Bahini in the east were achieved within that time frame, and can be attributed to the excellent co-ordination between the Indian Army, Air Force, Navy, and the Mukti Bahini.
Split into simpler sentences: The speedy conclusion was only possible because the objectives set by the Mitro Bahini in the east were achieved in that time. This was only possible due to excellent co-ordination between the Indian Army, Air Force, and the Navy and the Mukti Bahini.