The 3-ply masks made by many fly-by-night manufacturers are substandard and often lack the central filtration layer.
The middle ply of 3-ply mask, or surgical mask as they are also known, is made of a material called melt-blown fabric. It is made of a fine mesh of polyester that filters out microscopic infectious particles. The material is in short supply globally due to the sudden surge in demand and hence its price has soared, resulting in many mask makers skimping on it, said one manufacturer. And it could be a serious issue if these end up with healthcare workers.