Answer:
The very idea of the British Raj—the British rule over India—seems inexplicable today. Consider the fact that Indian written history stretches back almost 4,000 years, to the civilizationcenters of the Indus Valley Cultureat Harappa and Mohenjo-Daro. Also, by 1850, India had a population of at least 200 million.
There were draw and they wanted to keep it going
The Tang Dynasty of China when faced with rebellion from General An Lushan in their northern territories sought outside support from mercenary forces. This was done a number of times during the rebellion, these mercenaries were typically Arab, however, we also have examples of soldiers brought from Uighur to fight with the Tang and numbered in the thousands in the fight against Lushan's forces.
With the help of mercenary forces, the Tang were able to take back several important capital cities of China and effectively eliminated the rebellion of Lushan, as well as his later supporters and successors.
There is a detailed examination of his case at this link
http://www.washingtonhistoryonline.org/leschi/
Ive not read all of it myself but would expect the answer to your question to be there.
Unfortunately the "quashing" of his sentence came far too late to save him from being hung
