New Delhi, Dec 30 (PTI) In an ongoing district-level drive to contact and test UK returnees, many untraced cases have been found which furnished wrong or incomplete addresses and details like mobile phone numbers, officials said on Wednesday.

Over 3,900 passengers out of more than 14,000 who landed at IGI airport from November 25 have been found to have Delhi addresses, the officials said.

"In many cases the district teams have failed to find the UK returnees on the given address or mobile number, which are incomplete. Attempts are being made to trace them at the earliest," said a senior Delhi government officer.

In New Delhi district, a total of 592 people arrived from UK where a highly transmissible strain has been reported. Out of these, 226 were found to have duplicate or untraceable addresses, the officer said.

Such untraced cases have also been reported from other districts, officials said.

So far, 20 UK returnees who landed at IGI airport here have been found positive for coronavirus. These included 11 who underwent mandatory the RT-PCR test at the IGI Airport, while nine were tested positive in a door-to-door drive.