Singapore may be the saddest nation on Earth, but it's also one of the safest, with one of the lowest crime rates (not counting soccer-related crime). Which is what makes today's rioting in its "Little India" neighborhood especially surprising.

The trigger was the death of an unnamed Indian man who was hit by a bus. About 400 people, said to be South Asian migrant workers, then took to the streets, first going after the bus that killed the man and then setting fire to other vehicles and attacking officials. Either 16 or 18 people (depending on who you read) were hurt, mostly Singaporean police officers. The bus driver, who was not a migrant worker, was hospitalized.

Twenty-seven people -- all migrant workers -- were arrested. According to the BBC, Singapore's famously draconian punishments for rioting are up to seven years in jail (Wall Street Journal says it's 10 years) and caning.

As is the case with most riots, the underlying cause was much bigger than one fatal bus accident. Singapore's rising wealth has created significant underclass of migrant workers who often feel taken advantage of. There is no minimum wage in Singapore, for instance, and work permits that allow South Asian workers into the country are restrictive of their non-work activities. Workers retaliated with strikes and sit-ins in 2012. Those were met with deportations, fines and jail terms.

Singapore's deputy prime minister Teo Chee Hean dismissed any tensions, saying:  "By and large, the relationships are good" and "we welcome guest workers here who are law-abiding and who want to make a living for themselves."

Singapore's prime minister Lee Hsien Loong posted a statement on his Facebook page, saying:

The Little India riot last night was a very grave incident. Several police officers were injured, and vehicles damaged or destroyed. The situation is now under control, and investigations are underway. Whatever events may have sparked the rioting, there is no excuse for such violent, destructive, and criminal behaviour. We will spare no effort to identify the culprits and deal with them with the full force of the law.

I urge all Singaporeans to stay calm. Do send the Police any information, photos or videos of the incident that you may have. I also wish the injured officers a full and speedy recovery. - LHL

Singapore's last major riots were in 1969.