Traditional methods of garbage disposal, such as composting, sanitary landfill, incineration, etc., have their own advantages and disadvantages. However, due to poor garbage classification and the use of mixed collection garbage operation, garbage disposal often causes secondary pollution to water and soil resources, resulting in high waste disposal costs. At present, the treatment methods for urban household waste mostly involve direct incineration and landfilling, without the need for detailed classification and reduction treatment, resulting in significant pollution to the ecological environment and serious waste of resources. In this process, not only can recyclable resources not be effectively utilized, but some harmful substances such as soil and water pollution and subsequent treatment may also cause immeasurable harm to human health.

Before the reform and opening up, China's nascent solid waste industry was in the 1.0 era of "small-scale farming circulation and full utilization of resources". With the policy promotion of reform and opening up and the acceleration of urbanization, China's solid waste industry has entered the 2.0 era of "landfill+incineration". Since the Third Plenum of the 18th Central Committee, all parties have realized that the environmental problems left behind by the "landfill+incineration" model in the 2.0 era are increasingly deepening. China's solid waste industry has entered the 3.0 era of "turning passivity into initiative", aiming to help promote the comprehensive construction of ecological civilization. In September 2016, the National Development and Reform Commission and the Ministry of Housing and Urban Rural Development jointly issued the "Plan for Compulsory Garbage Classification System", which improved the laws and regulations on garbage classification and established a basic system for reducing, harmless, resourceful and industrialized household waste. Garbage classification has risen from individual public behavior to the level of national strategic development, thus achieving a high degree of consistency between national strategy and industry orientation in garbage classification policies.

46 key demonstration cities for garbage classification across the country are currently actively responding to the mandatory garbage classification policy. However, due to differences in population size and density, economic foundation, and target audience in different regions, the refined segmentation policies are also vastly different.

Research by E20 Environmental Research Institute shows that the source classification of waste in China is currently in its early stages and there is a significant gap in response levels among different regions. In terms of popularity, household waste generated by residents is divided into hazardous waste, recyclable waste, kitchen waste, and other waste. In addition, residents will also generate a large amount of decoration waste. With the development of the economy, every city is facing the problems of urban renovation, new housing construction, and renovation, resulting in a particularly large amount of construction waste. As for the classification of kitchen waste, Beijing, Shanghai, Guangzhou and other places activate the demand for kitchen waste treatment through a "unit first" approach, and gradually promote it comprehensively to residential areas through a "point to area" approach. Some cities, represented by Ningbo and Xiamen, adopt a two pronged approach of prioritizing kitchen waste treatment facilities and closely following the promotion of garbage classification, aiming to improve the "classified garbage classification and treatment" model.

Regardless of the classification policy, the characteristics of high mixing degree and high moisture content of mixed household waste in China remain unchanged. Although the mandatory classification policy can promote the transformation of mixed household waste into finely classified waste, the complexity of each classified waste is still relatively high due to the fact that the policy is still in its infancy and exploration stage in China. Such situations pose a severe challenge to the introduction of advanced waste sorting equipment and existing classification and treatment facilities.