A guest professor from a Beijing University resigned on Monday after stirring controversy as videos of him smoking in front of class were widely shared online.

The guest professor from the Communication University of China, surnamed Wang, reportedly told students that smoking would "inspire" him to teach better, and asked them to smoke with him if they wanted to, the Chongqing Morning Post reported citing one of the students in his class.

The educator prompted debate on smoking in public – a practice that has been banned in Beijing since 2015. Despite the criticism, many students have come to his defense on social media commenting on how much they enjoyed the guest professor's lectures.

In response, the university posted on Weibo, Chinese equivalent's of Twitter on Monday that Wang's behavior crossed the professional code of ethics for teachers, and violated the city-wide smoking ban in Beijing which strictly prohibits smoking in indoor public places, workplaces and public transportation.

The guest professor has also apologized on Weibo, saying he's determined to quit smoking and won't continue teaching if he fails.

Smoking in public in China has been treated as a serious issue in the recent years following a growing amount of anti-smoking campaigns across the country, as well as a handful of other urban areas joining in banning smoking in public places like Shanghai and Hangzhou.

The number of smokers in Beijing has dropped by about 200,000, three years after the city adopted its strictest tobacco control regulation, China Daily reported citing Beijing's health authority.

Similarly, last week, a university in northwest China's Shaanxi Province, stirred controversy after it used a fresh and humorous approach to advise students against tobacco use – with memes and slogans like "You won't find a girlfriend if you smoke."