NEW DELHI: The Centre has rapidly expanded Covid-19 surveillance to track thousands of migrant labourers going out of cities, particularly large ones like Delhi and Mumbai, to keep an eye on incidence of the disease in villages and districts where these workers are headed.Throngs of people walking along highways set off fresh concern in the government, leading to the National Centre for Disease Control setting up mechanisms to follow the migrant paths. It has identified districts and villages where a significant number of people are arriving in states like UP, Bihar and Rajasthan (among others) and tagged them as “high risk”.The quick shift in strategy was needed as officials monitoring the Integrated Disease Surveillance Programme (IDSP) were taken aback by the numbers setting off on treks despite the nationwide lockdown . The situation was seen in its humanitarian context as physically preventing people would be difficult, creating a law and order problem. “People were reacting to fears and concerns over livelihood and how long the current situation will last,” said a senior official.But with India locked down to prevent the virus from spreading into a wider community, migrant workers could be potential carriers of the disease into the hinterland, creating a serious healthcare challenge given that facilities for Covid-19 treatment are limited in rural areas. The tracking of migrants, with rapid response teams under the IDSP providing inputs along the way and at destinations, will give officials something to go by.While the exodus from major cities spells a new challenge for health authorities, officials said the situation could become stable in a few days. It is believed that those who needed to return home would largely have left cities and reached their destinations and there would be stable populations at both ends. “We will know there are some infected people in both locations and can hope that our tracking mechanism will bring them under scrutiny,” said the official.“We have already started the process to identify these districts and specific villages which are at high risk. We have asked states to ramp up preparedness at the district level and ensure facilities are extended to the last level in distant villages,” the official said, admitting that the walkers could hurt the objectives of the lockdown.“The lockdown is a process and we will see the results of the lockdown in the next few days,” Lav Agarwal , joint secretary in the health ministry, said at the daily briefing on Covid-19. He added that the lockdown would be successful only if people followed the government’s guidelines on isolation, social distancing and hygiene practices.Meanwhile, as part of its preparations to deal with a potentially large volume of cases, the Centre has directed states to keep some beds reserved for creating isolation facilities in public and private hospitals and ensure that stable patients are discharged as early as possible.It has also ramped up its lab network for testing, and ordered 40,000 more ventilators as well as augmented supplies of personal protection equipment and masks for healthcare workers.“The impact of the lockdown will be seen once the migrated population settles in their homes and we have all other means in terms of logistics, PPEs, ventilators, health resources in place. We are working in that direction,” the official said.