in 2020, china banned the annual ceremony for the first time in 30 years. police said the ban was needed for public health reasons related to covid-19, but critics say the ban is part of ongoing measures to stop political dissent. more than 12 activists first attended the june 4 ceremony despite the ban and thousands came later. the crowds broke through barriers set up around victoria park to light candles and sing songs. police later arrested over 20 activists, including leaders of the hong kong alliance in support of patriotic democratic movements of china, the group that organizes the yearly ceremony.