HONG KONG—Antigovernment protesters wreaked havoc on the city for a second straight day, with train services disrupted, schools closed and roads blocked a day after one of the bloodiest episodes of unrest in more than five months of demonstrations.

Protesters and police clashed across Hong Kong on Tuesday, including at universities and train stations, and in the city’s financial district. The violence intensified into the night, particularly at the Chinese University of Hong Kong, where police fired tear gas, water cannon...