She quit her job at state broadcaster CCTV, which had made her an instantly-recognisable celebrity, and launched into a one-year investigation into the human cost of China's notorious air pollution.

The result, a 104-minute documentary entitled Under the Dome, was posted online on Saturday, and has exploded into an unprecedented viral sensation, garnering well over 100 million views within 36 hours across various video-sharing websites and sparking vehement debate on a topic that resonates widely across China.

Ms Chai's documentary, which she says was self-funded, is compelling viewing. Presenting in front of a large screen on a dimly-lit stage before a small live audience, the slick production is reminiscent of Al Gore's An Inconvenient Truth – except even more engaging, as viewers pointed out, because of the strong personal element.

"I'd never felt afraid of pollution before, and never wore a mask no matter where," Ms Chai, 39, says in the video. "But when you carry a life in you, what she breathes, eats and drinks are all your responsibility, and then you feel the fear."

The documentary also stands out for its criticism of the government's role – including lax government regulation, state monopolies in the energy sector and China's headlong pursuit of economic growth –  in contributing to the country's toxic smog.

Rather than pull the documentary down from China's heavily-censored internet before it gained traction, it has even gained praise from senior government officials ahead of this week's National People's Congress in Beijing.

"Chai Jing's documentary calls for public environmental consciousness from the standpoint of public health," said Chen Jining, China's newly-appointed environment minister.  "It deserves admiration."

But while access to the video was not blocked, popular Chinese internet portals had removed prominent headlines and links to the video from their homepages, apparently at the instructions of propaganda officials – though this has not slowed the video's reach through continued sharing via other social media applications.

The Chinese government says it has made tackling China's air quality problem - one of the most visible and pervasive sources of popular dissatisfaction - a priority.

At last year's congress, Premier Li Keqiang said China would "declare war" on pollution, and similarly strong language is expected this week. President Xi Jinping remarked during last year's APEC summit that he'd start his mornings by checking the air quality reading on his phone, much like countless ordinary Chinese people.

The discussion comes at a time when China is seeking to balance continued economic growth with limiting further damage to the environment. Shanghai became one of the first provincial-level cities to remove a GDP target from the assessment criteria of senior officials.

While Ms Chai's documentary received widespread admiration for its perceived authenticity, it did not receive universal praise.

Critics accused her of hypocrisy, given she reportedly gave birth to her daughter in the United States. Scientists have also challenged Ms Chai's suggestion that her daughter's benign tumour, which was successfully removed after birth, was caused by exposure to pollution.