A blanket ban on public smoking has come into force in the Chinese capital Beijing.
Those who flout the rules will be named and shamed by the authorities and could face up to a fine of 10,000 yuan (£1,050, $1,600).
The law, which is one of China's toughest to date, prohibits smoking indoors and in public places like restaurants, offices, schools and some outdoor areas. Establishments where repeated offenders are caught also run the risk of getting their licences revoked.
"Restaurant staff have a duty to try to dissuade people from smoking. If they don't listen to persuasion, then law enforcement authorities will file a case against them," said Mao Qunan, of the National Health and Family Planning Commission.
Though China already has strict rules governing smoking, they have proved ineffective.
It is estimated that there are more than 300 million smokers – nearly one-third of the world's smokers – in China, the world's biggest tobacco consumer. In addition to that, nearly 740 million are exposed to second-hand smoke annually.
Official statistics suggest about a million people die in China due to smoking-related diseases, a death rate some 3,000 every day.
Anti-tobacco advocates have welcomed the ban but remain sceptical of its implementation.
The World Health Organization (WHO) has hailed the crackdown. Shin Young-soo, regional director of WHO Western Pacific Regional Office, said: "We applauded Beijing for its strong and determined leadership in protecting the health of its people by making public places smoke-free. We are delighted to be formally recognizing the Beijing Municipal Government with a WHO World No Tobacco Day Award."