Once upon a time, Singapore's roads were filled with street hawkers.

From the 1950s to 1970s, street hawkers such as this woman who was selling noodles at Siglap Market in 1970 were a common sight as many took to hawking for a living because unemployment was rife.

However, due to health and hygiene concerns, the Government decided to build hawker centres, where there would be a proper place to prepare food with a supply of clean water. After Singapore gained independence in 1965, one of the first things the Government did was to construct hawker centres and relocate some 18,000 hawkers to these places.

This week, The Straits Times features four black-and-white photos from the Singapore Press Holdings' archives that were colourised using the Government Technology Agency's new and free online tool that adds colour to old black-and-white photos almost instantly.

The tool, called Colourise.sg, takes about 3½ seconds to add colour to an uploaded photo.