Public housing started in Singapore in the 1930s. The Singapore Improvement Trust (SIT) carried out a building programme because there was not enough housing in the city. The SIT mainly built housing for middle and lower-middle class Asians at first. The Tiong Bahru estate is a typical example. It is a group of four-storey Art Deco style apartment blocks, shops, and markets outside the city center. After the war, the style changed from Art Deco to a simple, modern style.