Excerpts :
Sikh regiments made their way to the foreign quarter “crawling through the Imperial sewage canals”, undetected by the Boxers, and were the first troops to come to the aid of the besieged foreigners.
The lifting of the siege was one of only several key instances where Indian troops left an unlikely mark on the course of Chinese history in the early twentieth century.
On August 4, 1900, a relief force of more than 3000 soldiers from Sikh and Punjabi regiments left Tianjin, part of the larger eight-nation alliance that was dispatched to aid the besieged quarter, where 11 countries had set up legations. Sikh troops were also dispatched to guard churches and Christian missionaries, the targets of the Boxer uprisings.
Among the Indians, there was sympathy for the Boxers, Colonel Jaishankar said. Gaddhar Singh, a Rajput who was in Beijing in 1900-01, empathised with Chinese grievances in his accounts, arguing it was an entirely justified peasant rebellion.
The British also dispatched Indian regiments to China leading up towards the Opium War, which ended with the Treaty of Nanking in 1842 and the opening up of Chinese ports to the British.
The British deployed Sikh soldiers as law enforcement officers in ports like Shanghai, where their trading companies had set up a large presence by the early twentieth century. The Sikh soldiers were feared by the Chinese with their imposing figures, so much so that the British deemed that they did not even need guns when on duty, Colonel Jaishankar said, citing records from the time.
The history of Indian and Sikh troops in China is one that is ignored in Chinese accounts, and is likely a sensitive legacy considering they were often deployed against the Chinese.
with thanks : sikhsangat : link above