Increasingly, the future of the pro-democracy movement in Hong Kong is looking dim as its advocates suffer knockdowns, in what is being viewed here as yet another move by China to tighten its grip on a city ruled under the "one country, two systems" principle.

Last Monday, a Hong Kong court sentenced two former lawmakers to four weeks in jail for unlawful assembly inside the legislature while they were still lawmakers. Baggio Leung, 31, and Yau Wai Ching, 26, along with three assistants, were found guilty of unlawful assembly last month for attempting to barge into a room and scuffling with security guards in the Legislative Council in 2016.

Both activists had burst onto the scene two years ago following an election, and their rise represented a peak in Hong Kong's youth-led opposition movement. But it did not take them long to plot their own downfall, beginning with them insulting China during their swearing-in, which cost them much public support.

It was inevitable that the Hong Kong government would deem their oaths to be invalid, and a court in 2016 disqualified them from their legislative posts.

One need look no further than the traditional candlelight vigil on June 4 to notice the cracks in the pro-democracy movement, which highlighted generational differences between the Hong Kong Alliance in Support of Patriotic Democratic Movements in China and younger activists.

Student activists had argued for the event to focus on democracy in Hong Kong rather than in the mainland. Key student groups boycotted this year's event and police said 17,000 people, a thousand fewer than last year, turned up at Victoria Park last Monday to commemorate the 29th anniversary of the Tiananmen Square crackdown. Organisers, however, claimed 100,000 braved the rain for the vigil.

The fact remains that in the years since the Occupy Central pro-democracy movement in 2014, the turnout marking the Tiananmen anniversary in the city has been shrinking.