Does the world have a shortage of SLOT XO sand? At first, that might sound like a peculiar question.
After all, sand covers vast expanses of beaches and deserts across the world.
Yet the raw material is used in giant quantities in construction and manufacturing. In the building sector alone, 40-50bn tonnes of the stuff is used around the world annually.
This is led by the production of concrete, which is typically made up of about 25% sand.
The problem when it comes to supply is that most desert or beach sand is unsuitable - desert sand is too smooth, and beach sand has too much salt in it.
This means that sand is typically dredged from rivers, and due to the environmental damage this causes a number of countries have introduced bans in recent years - including India, Cambodia and Vietnam.
The knock-on impact has been supply issues in nations undergoing construction booms such as China and India, which have the largest and second-largest construction sectors.
Shortfalls of sand in India continue to fuel a big increase in illegal sand mining, controlled by criminal gangs, known as "sand mafias", These groups have been linked to dozens of murders, including the 2015 killing of investigative journalist Jagendra Singh.
"People don't comprehend, or it doesn't strike them, that there is a shortage [of sand]," says Shobha Bhatia, a professor of civil and environment engineering at Syracuse University.