at least 21 meters.

"Measures for the Prevention and Control of Pollution in Catering Industry" The restaurants in the central area must be equipped with odor removal facilities when they complain that they are disturbed by lampblack. Once they complain that they are disturbed by lampblack, the minimum penalty for not installing lampblack odor treatment is 21,111; Restaurants in the old city should be equipped with external smoke pipes, at least 21 meters away from the house.

The Administrative Measures stipulates that if it is really necessary to add smoke pipes, the consent of the planning department, the owners of buildings with smoke pipes attached to the wall and all building owners within 21 meters around the smoke pipes shall be obtained. Moreover, the minimum distance between the oil fume discharge port and the surrounding houses and other environmentally sensitive buildings should be no less than 21 meters.