It is rather unsettling to read of the sinkhole, which is "bigger than a football field and 3m deep", that opened up unexpectedly at a beach in Queensland, Australia ("Sinkhole at Queensland beach swallows vehicles"; Monday).
While the building of more train lines and other infrastructure underground will free up some surface land to accommodate the planned increases in our population, we should also be mindful of the potential danger of triggering the occurrence of similar sinkholes due to any excessive digging.
Many giant sinkholes have opened up in other countries ("Sinkhole 'devours' part of road in Brooklyn"; Aug 6, and "Florida villa collapses into 30m sinkhole"; Aug 14, 2013).
In Singapore, too, there have been several sinkholes reported ("Tipper truck caught in Upper Changi sinkhole"; April 25, 2014, "Sinkhole appears in C'wealth Ave West"; Dec 24, 2013, "Sinkhole at Woodlands Road patched, stretch reopened"; March 18, 2013, "3m-deep sinkhole appears in Clementi Road"; March 6, 2013 and "Circle Line work causes cave-in off Holland Road"; May 25, 2008).
Giant sinkholes like the one in Australia may not occur in the short to medium term here.
But there is no certainty that they will not appear in the longer term and endanger our future generations, if we were to continue digging unabatedly.
Ng Chee Kheon