Public smoking in China's capital, Beijing, is now banned after the introduction of a new law.
China has over 300 million smokers and over a million Chinese people die from smoking-related illnesses every year.
Smoking bans already existed in China, but have largely failed to crack down on the habit.
These tougher regulations ban lighting up in restaurants, offices and on public transport in Beijing. Thousands of inspectors will enforce the rules.
Repeat offenders will be named and shamed on a government website, according to the Reuters news agency.
The new law also cracks down on tobacco advertising across the city.
The World Health Organization has welcomed the new tougher regulations.
"When implemented, this new law will permanently bring clean air to all of Beijing's indoor public places - in doing so, protecting Beijing's more than 20 million residents from the deadly effects of exposure to toxic second-hand smoke," said its representative in China, Dr Bernhard Schwartlander.
However, others believe that the sheer popularity of the habit will make the regulations difficult to enforce.