Some sources for environmental data:
NUS Asia Research Institute (For example, see Publications tab--most all reports are open access)
Singapore: A Country Study, Library of Congress
Other country studies can be found here.
National Archives of Singapore oral history interviews, maps and plans, governmental records, photographs, sound recordings, posters, speeches
The Reef Ecology Lab, Department of Biological Sciences and Tropical Marine Science Institute, National University of Singapore
Biome, a single repository of biodiversity (flora and fauna, plants and animals information of Singapore) and environment-related data
CRISP Research Centre for Remote Imaging, Sensing and Processing, National University of Singapore
The applications of SAR and optical data in ocean and coastal studies, and tropical vegetation studies, including environmental monitoring, such as the daily monitoring of the regional land/forest fires and monitoring of ocean oil pollution.
The Coastal Environmental Profile of Singapore (1988) .pdf