In an attempt to check spread of a new, more infectious strain of coronavirus detected in the United Kingdom, the Delhi government on Tuesday said it would trace all passengers who have arrived here from the country. "Starting today, the Delhi government will conduct door-to-door testing for all those who have arrived in the city from the UK over the past two weeks," Health Minister Satyendar Jain told NDTV on being asked about the government's preparedness to check its spread in Delhi, where active cases have dropped to below the 10,000-mark after weeks of record infections and deaths amid a third wave of COVID-19.