“We will sacrifice ourselves for the people of Shifang,” reads a bold scrawl on the side of a building in the south-western Chinese town, captured in a picture on the Chinese microblogging site Weibo. “We are the post-90 generation.”

The small town of Shifang in Sichuan province is an unlikely place for a Chinese coming of age party. But an environmental protest, sparked by a plan to build a copper plant, has revealed a potentially important shift in the country’s politics: young people were at the forefront of the three-day demonstration, exposing a new vein of activism in a generation seen by many as apathetic.

China’s youngest generation – known as the “post-90” generation, born after 1990 – is just starting to graduate from university. But they are already making their mark.