Tens of thousands of students flooded the streets of Chile on Thursday in one of the largest demonstrations demanding free education.

After two years of student marches that have paralysed Chile’s major cities and generated expectations of change to a troubled system, the crisis over education reform remains a key electoral issue ahead of November’s presidential election.

Thursday’s protests were mostly peaceful. Students waved flags, chanted slogans and danced in the streets in a festive atmosphere recalling the creative marches of 2011, when thousands dressed as superheroes, staged mass kiss-ins and danced like zombies to Michael Jackson’s “Thriller.”

But the marches, which are often infiltrated by violent anarchist groups, also ended with clashes between police and hooded vandals. Police arrested 109 people, including 24 minors, and at least six police agents were injured.

Student organisers estimated the crowd in the Chilean capital on Thursday at about 150,000 people. City officials said the number was closer to 80,000.

Local media called it one of the largest marches in Santiago in more than two decades.

‘Here to stay’

The size of the protest showed the strength of the student movement in an election year, said student leader Camila Vallejo.

“This symbolises that the student and social movement didn’t go home and that that the movement is here to stay,” Vallejo told local ADN radio.

The protests began during the 2006-2010 government of Michelle Bachelet and grew into strikes and school takeovers that forced her to shuffle her Cabinet. Bachelet tried unsuccessfully to calm the movement by naming a committee to discuss student demands.

The protests have turned into a bigger headache for president Sebastian Pinera, whose government is focusing a chunk of the 2013 budget on financing school loans at lower rates.

But students say it’s not enough because the system is still fails them with poor public schools, expensive private universities, unprepared teachers and unaffordable loans.

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