Crowds are thronging central Barcelona and blocking roads across Catalonia in a protest strike over police violence during the independence referendum, BBC reported on Tuesday.
There is little public transport, after Catalan trade unions called the strike to show public anger at Spanish police tactics during Sunday's disputed vote.
More than 50 roadblocks caused big traffic jams. Barcelona port was at a standstill, union sources said.
However, the city's El Prat airport and its taxis are operating normally.
Many small businesses across Catalonia have shut for the day. Schools, universities and medical services are also closed or operating at a minimum level.
Barcelona's metro traffic was cut to a 25% service during rush hour and no trains at all at other times.
Top tourist attractions were also closed, including the city's famous Sagrada Familia church.
Mercabarna - Barcelona's massive wholesale market - was left deserted as some 770 food businesses closed for the day.
The strike was called in protest at "the grave violation of rights and freedoms" seen during Sunday's ballot. Almost 900 people were hurt as Spanish police tried to prevent voting, in a referendum declared illegal by the Madrid government.
Spanish Prime Minister Mariano Rajoy said the vote made a "mockery" of democracy.
Some police officers were seen firing rubber bullets, storming into polling stations and pulling women by their hair.
Thirty-three police officers were also injured in Sunday's clashes, Catalan medical officials said.
However, more than 2.2 million people reportedly voted in spite of this. The Catalan government says the vote in support of independence was nearly 90%, but official results have not yet been released.
Turnout was relatively low at a reported 42%, potentially weakening the position of Catalan President Carles Puigdemont.
On Monday evening the Spain national football team abandoned a training session after fans booed and whistled at defender Gerard Pique, who has strongly backed the Catalan referendum.
Guardia Civil police mingled among the crowd, as some fans waved Spanish flags and anti-Pique placards.
He plays for FC Barcelona, which announced that it had joined the strike. "None of the professional teams or the youth teams at FC Barcelona will train tomorrow," the club said on Monday evening.