A scaled-back version of the world’s biggest mobile fair got underway Monday in Spain under tight virus controls, with top firms avoiding an in-person presence after the pandemic derailed last year’s edition.

Spain’s King Felipe V and Prime Minister Pedro Sanchez were on hand for the opening of the four-day Mobile World Congress (MWC) in Barcelona, one of the first big technology conferences staged in Europe since the start of the pandemic.

“We are back to business, we are back to Barcelona, we are back together,” Mats Granryd, director general of the industry association that stages the congress, the GSMA, said in an opening address.

The event, which is usually held in February, is taking place this year both in-person at Barcelona’s main conference centre as well as digitally, with an online appearance by tech billionaire Elon Musk among the highlights.

Participants will only be allowed into the congress if they have a negative Covid-19 test result which is less than 72 hours old and will have to sign a daily declaration that they are in good health.

Dozens of people lined up outside a testing site on Monday morning to determine if they could be allowed in.

Once inside they must wear medical-grade FFP2 face masks at all times and follow a one-way walking system, although arrows on the floor indicating which direction to follow were largely ignored.

Organisers have limited attendance to 50,000 as part of virus control measures, compared with a normal attendance of around 100,000. They expect 30,000-35,000 people to actually attend.

The congress occupies just three halls of the congress centre this year, compared to eight in the past, with more speace between booths than in previous years.

Many major firms like Samsung, the world’s top smartphone maker, Nokia, Google and Facebook have pulled out of the in-person event, citing virus concerns although some will take part virtually.

China’s beleaguered Huawei, whose smartphone business has been battered by US sanctions, will be the biggest handset maker with a physical presence at the show alongside telecoms operators such as Orange and Telefonica.

Unlike in other years, no major phonemaker is scheduled to present a new flagship device at the event, which comes as global smartphone sales are rebounding after slumping in 2020 due to the economic havoc caused by the pandemic.

Global tech show CES, held annually in January in Las Vegas, was held virtually this year because of the pandemic.