Media playback is unsupported on your device Media caption What did Maryland university students think of the 'fresh air' speech

A Chinese student has apologised following a furious reaction to her US graduation speech that praised the "fresh air of democracy".

Speaking at the University of Maryland, Yang Shuping drew a parallel between air pollution in China and the country's restrictions on free speech.

Angry Chinese social media users accused her of denigrating her homeland and told her to stay in the US.

But the university backed her, saying it was vital to hear different views.

Ms Yang - who was selected by the university to speak - contrasted wearing a face mask against pollution with the "sweet and fresh" air in the US.

"The moment I inhaled and exhaled outside the airport, I felt free," she said in a video of the speech posted on YouTube.

"I would soon feel another kind of fresh air for which I will be forever grateful. The fresh air of free speech. Democracy and free speech should not be taken for granted. Democracy and freedom are the fresh air that is worth fighting for," she continued.

Her speech became one of the hottest topics on the internet in China, with posts about it having been viewed more than 50m times by Tuesday.

Media playback is unsupported on your device Media caption Ms Yang said the air in the US was "sweet and fresh"

Many Chinese social media users were angry, including fellow Chinese students at the University of Maryland who made their own YouTube video in which they accused Ms Yang of "false statements".

One of the students, Xinliang Jiang, said China was "still improving" and "needed to embrace suggestions from the outside world" but said Ms Yang's speech amounted to "deceptions and lies".

The city authorities in her home city of Kunming in southwestern China also weighed in, saying air quality had been good almost every day so far this year and adding: "In Kunming, air is very likely to be 'sweet and fresh'."

Image copyright YouTube Image caption Fellow Maryland student Xinliang Jiang accused Ms Yang of "deceptions and lies"

The People's Daily newspaper meanwhile accused her of making a "biased" speech.

Faced with mounting uproar, Ms Yang issued a statement on Chinese microblogging platform Weibo, saying she was "surprised and disturbed" by the reaction to her speech and "deeply loved" her motherland.

"I apologise and sincerely hope everyone can forgive me. I have learned my lesson," she wrote.

She was nevertheless backed by her university, which said in a statement: "Listening to and respectfully engaging with those whom we disagree are essential skills, both within university walls and beyond".

Some Weibo users agreed. "It looks like even if Chinese people go to America, they still can't have freedom of speech," one said.

Image copyright @Admjeinsbt Image caption Ms Yang's apology on China's Weibo microblogging service