It was late on Sunday night when officials in the southern Indian state of Andhra Pradesh received the alert. Federal authorities said they needed to track down more than 1,000 people linked to a large Muslim missionary gathering nearly 2,000 km away in the capital New Delhi.
Authorities in Andhra Pradesh, a region of about 50 million people, used cell phone towers, government databases and even village volunteers over the next five days to find almost everyone on the list — from attendees to the people they had been in close contact to fellow travelers.
The search is part of a nationwide manhunt for thousands of people linked to an outbreak of coronavirus at the headquarters of the Tablighi Jamaat group in a cramped corner of New Delhi, which is propelling a surge of cases in India, the world’s second most populous country after China.