BEIJING (Reuters) - When Chinese student Yang Shuping described how she ditched her five pollution masks upon discovering the “oddly luxurious” air of the United States, she drew a fierce online backlash, indignant newspaper columns and even a rebuttal from her hometown.

On Wednesday, the official Xinhua news agency’s English-language Twitter account broadcast a live-stream from Kunming, with two reporters interviewing passersby about air quality and whether they wore pollution masks.

“As you can see, most of the people don’t wear masks, but some do,” one of the reporters said.

China’s foreign ministry also weighed in, saying it was aware the issue was being widely discussed online, and that any Chinese citizen should “make remarks responsibly”.

Delivering her commencement address at the University of Maryland on Sunday, the psychology and theater graduate said that back home, she was forced to wear a face mask every time she went outside to prevent falling sick.

“When I took my first breath of American air, I put my mask away.” she said. “The air was so sweet and fresh, and oddly luxurious.”

“Democracy and freedom are the fresh air that is worth fighting for,” she said.

As the video went viral, and the online furor escalated over what was interpreted as an affront to China, netizens scoured Yang’s online presence for personal details, a process known in China as “human flesh search”.

They found Yang hailed from Kunming, capital of the southwestern province of Yunnan, a gateway to some of China’s most idyllic scenic attractions - and fresh air.

The revelation prompted a tongue-in-cheek retort from the city on its official Weibo social media account.

“We won’t take the rap for this! Up to May 8, the number of good quality air days in Kunming this year is 100 percent,” it said.

Netizens accused Yang of pandering to her American audience.

“Freedom of speech doesn’t mean not respecting the facts,” said one person on Weibo. “Trampling on China to praise the U.S., sorry I can’t agree with that.”

Yang apologized on Monday.

“The speech is just to share my overseas experience and comes with no intention to negate or belittle my country,” she said on Weibo, deleting earlier posts.

At a daily foreign ministry news briefing, spokesman Lu Kang said many students studying abroad would naturally experience a “development and change process” in how they see the world.

“As long as in the end they still ardently love the motherland, and are willing to make contributions toward it, I believe the Chinese government will encourage, support and welcome it,” he said.