From September, passengers in Europe will again have to limit the liquids in their hand luggage to 100 milliliters.

The European Commission described the move as a “temporary” and “precautionary” reintroduction. It affects the EU and the European Economic Area and follows the reintroduction of restrictions at British airports in June.

The reason for the reversal appears to be concerns about whether the latest CT or C3 scanners, recently installed at dozens of airports across Europe, can read bottles correctly.

C3 scanners are intended to make it easier for passengers to bring drinks and other large bottles onto an aircraft.

The EU’s U-turn does not affect the other main benefit of the new scanners: passengers no longer have to take their devices, such as computers and tablets, out of their bags to undergo a separate check.

In addition, most airports still use older X-ray scanners, which still require passengers to adhere to the 100 ml rule and the separate screening of certain electronic devices.

The Airports Council International Europe (ACI), an industry association representing the continent’s airports, described the EU’s rule change as a “setback” for passengers and a “blow” for airports that had invested heavily in purchasing and installing the new, state-of-the-art scanners.

The U-turn will result in “significant operational burdens” for airports, which will have to deploy more staff and reconfigure checkpoints, the ACI warned, calling on the Commission to communicate how long the reintroduced restrictions would remain in force.

ACI recently announced that European air traffic, measured by the number of airport passengers, had recovered to pre-pandemic or 2019 levels in the first half of 2024.