NEW DELHI: Containment operations will be scaled down if no secondary positive case of Covid-19 is reported from a quarantine zone for at least four weeks after the last confirmed test has been isolated and all his contacts have been followed up for 28 days, the Union health ministry said.According to the ministry's "Updated containment plan for large outbreaks Covid-19", a containment operation (large outbreak or cluster) is deemed to be over 28 days from the date the last case in that zone tests negative.The closing of the surveillance for the clusters could be independent of one another provided there is no geographic continuity between clusters. However the surveillance will continue for severe acute respiratory infection (SARI) and influenza-like illness (ILI). States shall ensure that all required steps are taken to contain clusters within the large outbreak and chain of transmission is broken, it said.The document stated that in India also, clusters and large outbreaks have been noted in parts of the country and unless they are contained in time, the risk of further spread remains very high. Large number of cases has been reported from Maharashtra, Delhi, Tamil Nadu, Madhya Pradesh and Rajasthan.The Centre has declared 170 hotspots ---123 hotspot districts with large outbreaks and 47 hotspot districts with clusters. Besides, it has identified 207 non-hotspot districts with clusters.In a bid to utilize the extended lockdown period to the maximum extent to contain the spread of coronavirus , states have been asked by the ministry to classify districts witnessing higher number of cases or high growth rate as hotspots, districts where some cases have been found as non-hotspots, and those which have reported no cases as green zones.According to the health ministry's document, "containment for large outbreaks through geographic quarantine strategy calls for near absolute interruption of movement of people to and from a relatively large defined area where there is single large outbreak or multiple foci of local transmission" of Covid-19.In simple terms, it is a barrier erected around the focus of infection. Geographic quarantine shall be applicable to such areas reporting large outbreak and/or multiple clusters of Covid-19 spread over multiple blocks of one or more districts that are contiguous based on the distribution of cases and contacts.According to the plan, the authorities will do extensive contact tracing and active search for cases in containment zone, test all suspect cases and high-risk contacts, isolate all suspect or confirmed cases, implement social distancing measures and intensive risk communication as part of the cluster containment strategy.For large outbreaks amenable to containment, the documents stated that the strategy will remain the same but vary in extent depending upon spread and response to be mounted to contain it.Geographic quarantine and containment strategy will include defining the area of operation, active surveillance for cases and contacts in the identified geographic zone, expanding laboratory capacity for testing all suspect cases, high risk contacts and SARI cases and operationalising surge capacities created for isolation (COVID-19 hospitals/blocks) to hospitalise and manage all suspect or confirmed cases.It will also include implementation of social distancing measures with strict perimeter control, providing chemoprophylaxis with hydroxychloroquine to all asymptomatic healthcare workers and asymptomatic household contacts of laboratory confirmed cases and further intensification of risk communication through audio, social and visual media."The objective of this containment plan is to stop the chain of transmission thus reducing the morbidity and mortality due to Covid-19," the ministry said.The death toll due to coronavirus rose to 420 and the number of cases in the country climbed to 13,387 on Friday, according to the Union health ministry.However, according to a PTI tally based on reports from the states, the total number of cases was 13,201 while 1,594 patients had recovered. The death toll stood at 444.There has been a lag in the Union Health Ministry figures, compared to the number of deaths announced by different states, which officials attribute to procedural delays in assigning the cases to individual states.