Unable to remove hard turmeric stains on the apartment common carpet
Tumeric is the most colorful component of curry. Good luck, tumeric can be used as a fabric dye. It doesn't come out of nice Brooks Brothers white shirts. 

Good Housekeeping suggests the following for curry stains in carpet: 


  Carpet
  
  
  Mix one tablespoon of liquid hand dishwashing detergent and one tablespoon of white vinegar with two cups of warm water.
  Using a clean white cloth, sponge the stain with the detergent/vinegar solution. Blot frequently with a dry cloth until the stain disappears.
  Sponge with plain water; blot until the liquid is absorbed.
  Sponge the stain with rubbing alcohol; blot to remove the stain.
  Sponge with water; blot until the liquid is absorbed.
  If the stain remains, mix one teaspoon of liquid hand dishwashing detergent and one tablespoon of ammonia with two cups of warm water.
  Sponge the stain with the detergent/ammonia solution. Leave it on the stain for at least 30 minutes, blotting every five minutes with a clean white cloth and more solution.
  Sponge with cold water and blot dry.
  


Personally, I would try it in an inconspicuous portion of carpet first in case it makes things worse in some way.