The sparky young performers on stage thank us for coming out tonight. There are so many other things we could have been doing, they tell us, before launching into their show, Too Much Sexual Freedom Will Turn You Into Terrorists. “Burning subways” gets the biggest laugh. We are, after all, in Santiago, where only three months ago people took to the streets and did exactly that. Even now, in spite of soaring summer temperatures, Chileans continue to protest every weekend. Their list of complaints ranges from inadequate private pensions to an out-of-touch president.

The graffiti creeping across every surface calls for an end to police violence, for the renationalisation of water and for the indigenous Mapuche people to fight back. Sprayed everywhere is the figure 6% – President Sebastián Piñera’s popularity rating.

While all that’s going on outdoors, things are just as polemical in the theatres. “We are in a special situation here, but Chilean theatre is always political,” says Carmen Romero, director of the Santiago a Mil festival, sitting in the sun outside Centro GAM, once the political headquarters of the Pinochet administration, now a city-centre arts complex. “Theatre is always thinking and writing about the social process.”

Facebook Twitter Pinterest ‘I’m making a show, while out there on the street is war’ ... demonstrators clash with riot police during anti-government protests in Santiago. Photograph: Edgard Garrido/Reuters

Nearly all of the dozen shows I see in the festival bear her out. Sometimes comic, sometimes earnest, always indignant, Chilean theatre repeatedly gives voice to the abused, the angry and the dispossessed. In Too Much Sexual Freedom, directed by Ernesto Orellana Gómez, four performers turn a panel discussion into a confrontational cabaret about fat shaming, HIV prejudice, discrimination against sex workers and trans rights. Upfront and ribald, they perform with intelligence, humour and an impassioned sense of injustice. “Let’s decolonise gender,” they say, as they pick apart forces of oppression lying deep in Latin America’s history.

Gender and power are also on the mind of director Stephie Bastías in The Tower, an all-female adaptation of Alejandra Pizarnik’s The Bloody Countess. It’s inspired by the myth of 16th-century Transylvanian countess Elizabeth Bathory; her insatiable taste for blood threatens the lives of her servants, who we find planning a pre-emptive strike. High on gothic melodrama and hand-wringing excess, it’s an uneven piece, but its call for unity in the face of tyranny echoes what’s going on in the streets.

Chilean theatre gives voice to the abused, the angry, the dispossessed

A sharper show is Dragón by Guillermo Calderón. It was written before the October emergency, but the playwright, a frequent visitor to the UK, is amazed to see how topical it has become. Like a polemical take on Yasmina Reza’s Art, it is about a collective of conceptual artists whose every attempt to create Augusto Boal-inspired “invisible theatre” on the streets throws them into ethical dilemmas about class, race and representation. Is it right they should re-enact the assassination in 1980 of Walter Rodney, a Guyanese political activist, or are they merely reinforcing cliches about Africa and violence? If they play the roles of Brazilians, will they be making assumptions about the immigrant experience? Funny, slippery and energetically acted, the three-hander satirises artistic vanity even as it recognises the value of political engagement. “I’m making a show, while out there on the street is a war,” one laments.

Facebook Twitter Pinterest Vivid sense of family … Trewa. Photograph: Danilo Espinoza Guerra

All this is consistent with a festival that has its roots in the underground resistance to the Pinochet dictatorship. Fiercely independent, Santiago a Mil sees itself on the side of the people and has accessibility in its DNA; the three-week festival attracts audiences of 200,000, of whom 150,000 pay nothing. “Theatre and people are together here,” says Romero.

This can mean there are times when political import and giving voice to the voiceless outweigh other considerations. Love to Death, created by Samoan choreographer Lemi Ponifasio, fuses the mournful Mapuche song of Elisa Avendaño Curaqueo and the controlled flamenco moves of Natalia García-Huidobro in a lament for Camilo Catrillanca, a young indigenous man killed by the police’s “jungle commandos” in 2018. For all its butoh-influenced restraint, it is a slow wallow in grief that lacks dramatic momentum. You sense it gets a standing ovation less because of its insight than for the import of what it stands for.

Facebook Twitter Pinterest Giving voice to the voiceless ... Love to Death. Photograph: Lemi Ponifasio

Going deeper into the story of state violence in southern Chile is Trewa by KIMVN Teatro. It’s a sorrowful look at a community’s response to the suspicious death of environmental activist Macarena Valdés in 2016 and the police shooting of teenager Brandon Hernandéz Huentecol the same year. The large production is set around a kitchen table where all generations congregate, creating a vivid sense of family and friends united in a David-and-Goliath struggle. So plain are the injustices – many simply stated as a voiceover itemising the numbers of executed and disappeared – that the actors seem less angry than disappointed.

As a play, it is more conversational than dramatic, but when the whole audience erupts into chants of “libertad” at the end, the division between art and life appears seamless. Indeed, Santiago’s curtain calls often feel incendiary. Having taken a bow, the performers will place a hand over one eye, a gesture of solidarity with the scores of protesters blinded by rubber bullets and teargas canisters in recent months. It raises the emotional temperature every time.

“This is a very special edition of the festival because of the emergency,” says Romero, who had to cancel street theatre performances and schedule daytime shows to keep the festival going. “We are living in a crisis and we need the opportunity to talk about what is happening.”