Answer:
it could be used to separate solid from liquids such as draining noodles, or to hold small fruits or veggies while they are rinsed.
it could also be put in a pan after water is added and then filled with vegetables to be steamed.
It can be used to drain out the unwanted dirt/mud/soil particles off of a bunch of leafy vegetable like spinach, fenugreek etc. while washing these under running water.