London: Climate activist Greta Thunberg went on trial Thursday for refusing to leave a protest that blocked the entrance to a major oil and gas industry conference in London last year. Thunberg, 21, was among more than two dozen protesters arrested on October 17 after preventing access to a hotel during the Energy Intelligence Forum, attended by some of the industry’s top executives.London: Climate activist Greta Thunberg went on trial Thursday for refusing to leave a protest that blocked the entrance to a major oil and gas industry conference in London last year. Thunberg, 21, was among more than two dozen protesters arrested on October 17 after preventing access to a hotel during the Energy Intelligence Forum, attended by some of the industry’s top executives.