Commenting on a "digital twin" of Singapore being built under the Cooling Singapore project to help researchers study factors affecting outdoor temperatures, SMU Associate Professor of Science, Technology and Society Winston Chow, a Cooling Singapore project principal investigator, said cooling strategies that can be implemented at new sites will differ from those in existing estates, which may need more retrofitting. "Some solutions that could work at existing estates could include, for example, having larger park spaces, green roofs and green walls, or having better technology, such as solar thermal hybrid air-conditioners, to reduce waste heat inputs into the urban climate," said Assoc Prof Chow.