Skin products that claim to not clog pores may be labeled noncomedogenic or non-acnegenic. The freezing water that saturates the fuel will sometimes clog the fuel injector pump. Also, any insoluble debris in the liquid can easily clog the tube. The air intake filter tends to clog up with sawdust. The slime can sometimes clog up enemy fishes' gills, causing them to die. Particulates in the raw oil clog downstream processes; sulfur and nitrogen create air pollution. Hard water also forms deposits that clog plumbing. This may cause the filter to clog and interfere with the regeneration process. Particulate matter can clog stomatal openings of plants and interfere with photosynthesis functions. Control valves may also clog or get stuck. As a result, the toilet doesn't clog easily. As a result, they clog their intestines which results in death by starvation. In addition, fibers from cotton and wool swimsuits could clog pool filters. Private vehicles clog the city daily, hampering mobility and creating pollution. The pressure sometimes knocked apart poor plumbing without blasting free the clog.