hong kong thirteen hong kong universities academic institutions accuse chinese-ruled city leader undermine freedom expression amid row pro-independence banners appear campuses hong kong former british colony return china 1997 guarantee freedoms high degree autonomy one country two systems arrangement include freedom expression start academic year banners advocate independence china appear noticeboards least seven universities large black banners hang across build hong kong leader carrie lam criticize posters violation china sovereignty urge university administrators take appropriate action colleges include prestigious chinese university describe posters unconstitutional allow remain late sunday 13 institutions issue statement title arm dark hour criticize lam university authorities explicit effort limit freedom expression student unions stress everyone enjoy freedom speech line shall never compromise ... ready defend right liberty read observers say controversy could use justify another squeeze city freedoms soon several young pro-democracy leaders jail help lead city massive occupy pro-democracy civil disobedience movement late 2014. row also stoke tension local mainland students comprise sizeable part university admissions especially post-graduate study call independence rare financial hub begin gain traction 2014 protest disillusionment grow toward china perceive tighten grip late last year two pro-independence lawmakers disqualify office beijing parliament rule oath-taking carry dig china beijing resolutely oppose talk hong kong split china mini-constitution state city inalienable part country so-called basic law also enshrine freedom expression group students side face several occasion mainland students put anti-independence posters condemn call independence one female student china film challenge tear pro-independence banners talk democracy put banners pull say video official blog run china state mouthpiece people daily sunday publish long editorial say limit freedom expression hong kong laws public order could use jail trouble makers quite apparent beijing hong kong government would like use excuse impose political crackdown say political commentator joseph cheng certainly pro-beijing establishment ask rapid legislation controversial article 23 legislation cheng add refer propose national security laws would criminalize perceive act sedition pro-independence china posters appear hong kong campuses stoke new tension