Technical standards refer to the technical regulations on the quality, specifications and inspection methods of industrial and agricultural products and engineering construction, as well as the graphics and symbols commonly used in technical documents, and are a common basis for production and construction. According to the above definitions, Which of the following are technical standards:. ['National regulations on quality standards for infant milk powder.', 'National Standards for the Evaluation of Healthy Cities.', 'National regulations on recall of defective products.', "Industrial Bureau's testing standards for smoke and dust emissions from metallurgical machinery plant equipment."]