In an operation that lasted five days, Delhi Police this week evacuated 2,361 people from the Markaz Banglewali mosque in Nizamuddin. In what could be the biggest cluster spread of Covid-19 in India yet, the meeting of the Tablighi Jamaat was the reason behind 20% of total reported cases so far, with 19 casualties across different states.The number is expected to still rise as test results of nearly 8,000 more followers as well as people who came in contact with them after the gathering are still awaited.On Wednesday, the police sealed and sanitised the Jamaat building. Residents of adjacent buildings have been asked to stock up and lock themselves in until the area is completely sanitised. Cops also sanitised Nizamuddin police station that shares a wall with the Markaz masjid.The fateful gatheringThe Jamaat held a religious congregation at its New Delhi headquarters in early March, where thousands of people who took part included senior preachers from Saudi Arabia, Malaysia and Indonesia where Covid-19 had already spread.After the congregation, participants left for various states, some of whom later developed symptoms of Covid-19. It all, however, went unnoticed until a 65-year-old man, resident of Jammu and Kashmir, died last week.Since then, Tamil Nadu, Telangana, Kerala, West Bengal, residents of states who visited, have reported cases linked directly or indirectly to the congregation.Nation-wide huntThe government identified it a ‘virus hotspot’ and quickly worked to seal off the area and trace everyone who had links to the meet. In Telangana alone, more than 700 of those who attended the gathering have been quarantined, with 9 dead.Among all the affected states, Tamil Nadu faces the biggest problem where 1,500 people attended the Delhi event, out of which 658 have been identified. Of these, 190 have tested positive.In Karnataka, out of the 1500 people who attended the congregation, so far 190 have tested positive, and 250 people, including foreigners, have been quarantined. There has been 1 casualty in the state till now.In West Bengal, out of 100 people who attended the congregation, 54 have been traced and quarantined so far, while 16 still remain untraceable. From Uttar Pradesh, 569 people attended, of which 500 have been identified and put in isolation. 69 people are still untraceable.Quarantine efforts were also underway in the states of Andhra Pradesh and Assam, where the number of untraced persons is much higher.Track and traceTo trace the others, police in different states have not only roped in specialised units such as the anti-terrorism squads, but surveillance methods are being used, a Times of India report stated.The police are also tracking phones, SIM locations, and even conducting door-to-door searches in different parts of the country, another report by The Print said.The complete footprint of that fateful meet has not been fully traced yet. But there are enough early indications that a more serious phase of the contagion in India has likely begun.