I am not familiar with sugarcane or cotton plantations, but I can explain the relative presence of Indians and Chinese in the mining and plantation industries for a small corner of the British Empire, which is Malaya and Singapore. Malaya was the world’s largest exporter of tin and rubber, so there were many tin mines and rubber plantations in the colony.
Let’s first look at how the British ran Malaya and Singapore. The East India Company, and later the British government, did not want to be an autocratic, intrusive dictatorship with full control over the lives of everyone in the colonies. Malaya ran on a free market economy. For example, the colonial government did not directly develop mines and plantations. Instead, this was left to private individuals and companies. There was also free movement of labour - people could choose what they wanted to work as and the colonial government couldn’t care less. There was no way the colonial government could ‘send’ a group of people to a plantation and order them to work - it just wasn’t set up to exercise that amount of control.
There was one exception to this, and that was if the people in question were criminals. From 1825 - 1873, the Malayan states of Penang, Malacca and Singapore acted as penal destinations for transported convicts from India. Convicts were supposed to serve out their terms providing labour for these three colonies. Criminal justice and sentencing were under the purview of the colonial government, thus they were put to work on colonial government projects. This included the building of roads, lighthouses, prisons and other government buildings, rather than working in private enterprise like mines and plantations.
There were exceptions - convicts with excellent records and who had remained in the colonies for at least 16 years were allowed to seek their own employment to earn a wage and learn a skill. However, they were still required to appear at muster once every 15 days, or whenever required. This made it impossible for them to work in the mines, which were located far from the prisons.
Now onto the question of how the Chinese ended up dominating the mining industry. This was not a result of deliberate policy by the British. Rather, the Chinese had been heavily involved with mining in Southeast Asia since the 1700s. This was a result of 3 factors:
These 3 factors made China the preferred labour source for developing the gold and tin mines of Southeast Asia. By the time Malaya was colonised by the British, the Chinese were not just working on the mines, in some cases they were also financing their development. At this time, there were also established means for bringing in more Chinese labour. If a mine required manpower, miners might write home to their relatives to inform them of the job opportunities. There were also agents who specialised in arranging for the emigration of Chinese labour. China thus continued to be the preferred source of manpower for mines in Singapore and Malaya.
On the plantations, China was also a primary source of labour in the 1700s. However, Chinese had been replaced as the principal labourers by Indians by the 1860s. These had been recruited from India and were much cheaper than their Chinese colleagues - in pre-war Malaya, an Indian rubber tapper would earn 10-15 dollars a month, while his Chinese colleagues could expect to earn 30-35 dollars.
In summation, Indians who were ‘sent’ to Malaya and SIngapore were convicts who generally constructed public works rather than working in privately owned mines. Indians who worked on the plantations of Malaya were foreign workers who signed contracts with plantations. They were cheaper than Chinese labour, allowing them to dominate the plantations. However, Chinese continued to dominate tin mining, probably because of long-standing labour arrangements and Chinese capital.
Kamble, A. A. (2007). INDIANS IN THE PLANTATION INDUSTRY OF MALAYA (MID19TH –20TH CENTURY). Proceedings of the Indian History Congress, 68, 1168–1177.
KIAN, K. H. (2013). Chinese Economic Dominance in Southeast Asia: A “Longue Duree” Perspective. Comparative Studies in Society and History, 55(1), 5–34.