Bring out the Guilotines!

Singapore has relied on foreign workers ever since its founding by Raffles. The difference may be that the British aggressively imported Chinese along with Indians (predominantly Tamils), and that the Chinese quickly displaced the ethnic Malays as the dominant ethnic group. (Indians were sent to almost all British colonies, as soldiers, police, money lenders (chettiers), civil servants, etc.). Ethnic Chinese dominated at Independence in the early 1960s, opted out/were kicked out of Malaysia because of Chinese dominance, and they continue to marginalize Malays, Indians, and Mainland Chinese. The latter they bring in for manual labor, and Singaporean Chinese look down on them for a variety of reasons. The ethnic Chinese, through the People's Action Party, maintain a one-party state (yes, there are other ethnicities in the PAP...) that continues to exploit ethnic minorities. Part of the problem, of course, is Singapore's rapid economic development and the quandary that comes with that -- how to maintain the population when the highly educated fail to reproduce at proper numbers. Part of their answer is the State Commission on Procreation and Marriage, essentially a state-run dating service that encourages, through financial incentives and disincentives, for educated people to make babies. Singapore is a truly bizarre place.

Singapore is basically a family run operation, certainly its more democratic than it used to be, but its pretty autocratic.
There have been Indians, as mentioned above, mostly Tamils who are full fledged citizens, for decades. About 10% of Singapore is of Indian descent, and demographically, those Indians are better educated and wealthier than the average Singaporean.
So racism against Indians, in and of itself, is not the cause of this riot- it is, instead,the standard use of low paid foreign workers, just like in the USA, Italy, Argentina, England, or South Africa- a standard business practice in far too much of the world.
That said, I have read reports that the single fatality was drunk, and fell in the path of a bus...

But didnt this happen over a month ago?

Spore treats their guest workers better than Dubai. So much that they want to stay. In the meantime, their rich are actually living overseas (the uw and our community colleges are full of their kids). The powerful want to keep a cultural identity, but they aren't there. The people there want to create a culture, but get denied. It's a truly 21st century cosmopolitan place that most Americans would never grasp anything about, at least the ones who want to pretend American culture solidified in 1955.

@3 They certainly don't have the "luxury" to protest; Singapore is not a democracy, it's a "soft" or "paternal" authoritarian system. As @4 states, it's opening up a little, but not much. Protests are not part of this opening, and protestors find themselves in jail and in court, sometimes with the government going after their wealth through the courts. India, however, is a democracy, one does have the right to protest there, and protests frequently occur. Your statement that South Asia is "FAR FAR FAR worse for them" is subjective -- some people would rather have political rights rather than wealth. Most Singaporeans I know openly accept the fact that their tradeoff -- wealth for political rights -- is one they think is worth it. The paradox is that wealth, when it generates a middle class, also generates demands for more political openness (although people such as Fukuyama argue that there are cultural constraints, in Singapore's case, Confucianism, but I think that's bullshit), and it may be occurring slowly now.