I'm living in an old three-room HDB flat which has a kitchen floor that is lower than the rest of the flat. Is it possible to raise the floor to match the rest of the space?
The difference in height between your kitchen and living spaces was created for a very good reason — the step kept water from the kitchen from flooding the living space during floor washings. For modern lifestyle, however, where less heavy cooking is done (unlike in the past), most kitchen floors would just require a light mop to clean off the oil and grease that might settle.
If you want to level the spaces, you can, but you have to apply for permission from the HDB before you proceed. You also have to use the appropriate concrete, according to the HDB rules, to raise the floor.
To achieve a more seamless connection of spaces without physically raising the floor, use new flooring to visually "bridge" them. One good example is shown above. Using black-and-white floor tiles in a staggered graphic motif for both spaces separated by the step disguises the difference in levels.