How are the low-, medium- and high-risk areas graded? What is the significance of categorization to COVID-19 response?

Beijing's categorization criteria are based on three factors, said Wu Zunyou, chief epidemiologist of the Chinese Center for Disease Prevention and Control, at the 145th press conference on Beijing's COVID-19 response on the afternoon of 8 July.

First, the basic geographical unit of categorization is neighborhood or township. Second, the time span considered is 14 days, the maximum incubation period of the novel coronavirus. Third, the number of cases and whether or not cluster cases exist are important yardsticks. For a specific neighborhood, the grading is based on whether and how many confirmed cases there have been in the past 14 days. There are now one high-risk and 18 medium-risk areas in Beijing according to the current criteria, which may be adjusted in light of the evolving COVID-19 situation. The categorization is part of the science-based and targeted containment measures to bring the virus under effective control while minimizing impact on people's life and work and the society at large.