Thirteen police officers were hospitalised after they were splashed with an unidentified liquid that was believed to be drain cleaner during the violent clashes on Lung Wo Road, Tim Mei Avenue and Harourt Road around the city's legislative and administrative centre, reports the South China Morning Post.
In an unprecedented retreat, the government moved its main celebration indoors at the Hong Kong Convention and Exhibition Centre in Wan Chai, from where attending dignitaries watched a live broadcast of the flag-raising ceremony at Golden Bauhinia Square.
The city's leader, Chief Executive Carrie Lam, broke with tradition to talk about self-reflection over her mishandling of the now-suspended extradition bill, rather than Hong Kong's development in the national context.
Lam gave a six-minute speech in which she largely concentrated on the lessons she would learn from the political crisis that has engulfed her administration as a result of the bill.
This marked her first appearance in public since apologising on June 18 over the controversial legislation which would have allowed the city to send fugitives to jurisdictions with which it did not have an extradition agreement, including mainland China
Although Lam suspended it on June 15, protesters are insisting she drop it altogether.
"I will learn the lesson and ensure that the government's future work will be closer and more responsive to the aspirations, sentiments and opinions of the community," she said.
On Sunday, thousands of pro-Beijing protesters rallied in support of the territory's police.
The handover on this day in 1997 marked the end of British rule in Hong Kong.
( With inputs from IANS )