between whom did it take place?
Between the Allied forces and volunteers of Singapore's population and the Japanese.
History of Singapore
Several fights by the Allied forces and volunteers of Singapore's population against the advancing Japanese, such as the Battle of Pasir Panjang, took place during this period. 
what developments have taken place that led to modern day singapore river UNANSWERABLE which colonial power has ruled here? Britain. which wars have they faced in the past? Battle of Pasir Panjang. when did it happen? 12 to 15 February 1942.
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History of Singapore [SEP] 1942–1945: The Battle for Singapore and Japanese occupation
Several fights by the Allied forces and volunteers of Singapore's population against the advancing Japanese, such as the Battle of Pasir Panjang, took place during this period. However, with most of the defenses shattered and supplies exhausted, Lieutenant-General Arthur Percival surrendered the Allied forces in Singapore to General Tomoyuki Yamashita of the Imperial Japanese Army on Chinese New Year, 15 February 1942. About 130,000 Indian, Australian, and British troops became prisoners of war, many of whom would later be transported to Burma, Japan, Korea, or Manchuria for use as slave labour via prisoner transports known as "hell ships." The fall of Singapore was the largest surrender of British-led forces in history.