Many schools during the Soviet era had military style uniforms. White shirts, brown short pants, and white kneesocks are a common style. Most Singapore schools seem to require short trousers for boys up to about 14 at least. No blazers though because it is too hot. The elementary winter uniform often includes short pants and knee socks.
Many schools have and a simple summer uniform of grey shirt and shorts for the summer.
School uniforms are commonly worn in Thailand. The uniforms at a typical school is a white shirt and black or kacki shorts for a boys and white middy blouse, dark blue skirt, and dark blue bow for a girls. However each schools has there own distinctive uniforms. I'm not sure, however, just when this fashion was prevelent. Summer uniforms of kahki shirts and short pants are also common.