Passengers catching flights from Calcutta will be denied what is considered a basic facility at most airports — inline baggage screening — at least till mid-January, officials said on Tuesday.

Those who will fly out during the Christmas-New Year holiday season will have to stand in a separate queue to get their baggage scanned, raising the possibility of flight delays.

At airports where inline screening is in place, passengers deposit their check-in baggage at the airline counter before collecting their boarding passes, without getting them scanned at standalone X-ray machines.

Inline baggage screening was supposed to become operational at the airport after Puja. But the rollout had to be deferred because tests conducted by Transportation Security Administration (TSA), which functions under the US department of homeland security, have revealed some problems, officials said.

The software installed in the inline baggage screening machines at the city airport was procured seven years ago and needed to be upgraded, the officials said. There were some hardware problems, too.

“The diverter, which guides a piece of baggage on the conveyer belt of the baggage screening system from one direction to another, became slow,” said an official.

Also, when the machine was tested with full capacity, it was developing snags and getting stalled.

“Siemens, which has provided the machines, has upgraded the software according to TSA’s recommendations and also resolved the hardware issues. The company is still running checks,” said Kaushik Bhattacharya, director of the airport.

“The TSA team is likely to come for an inspection again in the middle of December. Even if everything is fine then, the system cannot be made operational before the middle of January.”

Once TSA gives its nod, the airport will seek the final clearance from the Bureau of Civil Aviation Security.

Airline officials say passengers keep complaining about being forced to stand in an additional queue only to get their baggage scanned, which at times lead to flight delays.

“Delays happen mostly on weekends, when the passenger count rises, especially on international flights. With the number of passengers increasing almost every month, we need the system badly,” an official of an airline said.

Inline baggage scanning was introduced in the international section of the city airport in 2016. It has been withdrawn temporarily pending an upgrade.