Social prevention and control: First, send the police force to the front line to the maximum extent, invest in key areas such as residential areas, food markets, shopping malls, supermarkets, etc., patrol and guard 24 hours a day, so that the masses can see that the police are always on duty and safety is around. The second is to organize the police to station in the nucleic acid screening site and do a good job in order maintenance, crowd guidance and epidemic prevention tips. And ensure the smooth progress of tens of millions of nucleic acid screening. The third is to deploy more than 600 police officers in the city's reception hospitals to do a good job in on-site and off-site safety management, police handling and serving the masses. Strict control over the closure of residential areas: First, the public security police and all forces form a grid inspection team to strengthen the inspection of residential areas and resolutely implement the requirement of "people don't move and stay indoors". The second is to comprehensively use video patrols, drones and police helicopters to patrol at high altitude, strengthen inspections and publicity tips, and persuade people to go out without authorization and persuade people to gather for talks. Third, relying on "science and technology+manpower", we will combine big data analysis with basic work at the grassroots level, give full play to the advantages of "being familiar with the region and people", increase the intensity of "sweeping the building" and "patrolling the street", and urge some "easy-to-miss" personnel to complete nucleic acid testing.