This is a short history of civil defence shelters in Singapore: 

• 1983: The construction of the first public shelters started by hardening nine underground MRT stations on the North-South and East-West Lines. 
• 1987: A comprehensive shelter programme began with public shelters at void deck of new HDB residential blocks. Since then, public shelters have also been built in secondary schools, community centres and other public buildings.
• 1994: It was announced that Household Shelters would be built inside new HDB flats. This enables residents to have quick access to protection in a war or an emergency. Therefore, the practice of building public shelters at the void deck of HDB blocks was discontinued. However, the programme to incorporate public shelters in secondary schools, community centres and other public buildings continued.
• 1997: Under the Civil Defence Shelter Act 1997, new houses and flats must have household / storey shelters incorporated into the development. Applications for planning permission for new flats or houses to Urban Redevelopment Authority (URA) must therefore include household or storey shelters.