Government authorities are tackling a logistical nightmare as they try to map the movements of thousands of people who attended the Tablighi Jamaat congregation end-February and early March in New Delhi and then dispersed, many carrying the novel coronavirus to states across the length and breadth of India.

from Times of India https://timesofindia.indiatimes.com/india/nizamuddin-corona-cases-govts-race-to-curb-spread-as-hundreds-from-tablighi-meet-show-coronavirus-symptoms/articleshow/74921860.cms