The Spanish PP government is taking very repressive measures, including the arrest of Catalan government officials, in an attempt to prevent the referendum called for 1st October from taking place.
Police are also seizing ballot materials, etc, and local mayors have been threatened by police if they organise the referendum.
Political activity supporting the right of self determination has been banned in Madrid and other areas. The government has also threatened to suspend all autonomous rights of the Catalan government.
This has provoked an explosive reaction in Barcelona. Spontaneous demonstrations have broken out all over the city.