Complex sentence: In these circumstances, the Japanese Military Administration encouraged various Indian nationalist groups in East Asia to form an anti-British alliance, which came together to form the Indian Independence League (IIL), with its headquarters in Singapore.
Split into simpler sentences: In these circumstances, the Japanese military administration encouraged the various disparate Indian nationalist groups in East Asia to form an anti-British alliance. These came together to form the Indian Independence League (IIL), with its headquarters in Singapore.