Sort by what the item is made of. A blood bag is a contaminated plastic container, so place it in the stream meant for infected recyclable plastics.
Under the colour code, that stream is the red bag, which collects intravenous tubing, catheters, urine bags and blood bags for disinfection (autoclave or microwave) followed by recycling.
Rule out the rest by their categories: yellow takes anatomical and highly infectious waste meant for incineration, black holds ordinary non-infectious dry office and ward waste, and white is the rigid puncture-proof box reserved for metal sharps like needles and blades. A blood bag is none of these; it is infected plastic. So the answer is the red bag. Ref: Biomedical Waste Management Rules 2016; Park PSM.