A chemical mechanical polishing pad. The pad contains a water-insoluble matrix and Water-soluble particles dispersed in the water-insoluble matrix material and has a polishing surface and a non-polishing surface on a side opposite to the polishing surface. The pad has a light transmitting area which optically communicates from the polishing surface to the non-polishing surface. The non-polishing surface of the light transmitting area has a surface roughness (Ra) of 10 pm or less.