Qi Xingming woke up on Monday morning and took his place on the frontline of China’s war on cigarettes. Wearing a red armband and a panama hat emblazoned with the name of a Brazilian footballer, the 60-year-old migrant worker made his way to one of Beijing’s top hospitals and began his hunt for illegal smokers.

“When I say stop, they stop,” said Qi, one of around 1,100 “anti-smoking inspectors” deployed on the streets of the Chinese capital by the Communist party as part of a renewed crackdown on tobacco in one of the world’s most cigarette-addicted nations.

Beijing is home to around 4.2 million of China’s 300 million smokers, according to official figures. But under rules that came into effect on Monday they are now forbidden from smoking in all public places.

Cafes, bars, restaurants, hotels, schools, railway stations and hospitals – such as the one where Qi normally works as a cleaner – must now be entirely smoke-free, according to the regulations.

Smokers who flout those rules face fines of 200 yuan (£21) while business owners who allow them to do so could be forced to pay 10,000 yuan.

China’s state-run media urged its citizens to get behind the campaign. “This time we should mobilise everyone,” Gregory Tsang, an anti-tobacco campaigner, told CCTV’s lunchtime news, urging viewers to snitch on smokers by calling a special hotline or sending photographs of offenders to a recently launched social media account.

Campaigners say the new rules are some of the toughest in Asia but stubbing out smoking in a country with such a long-standing love affair with the cigarette will not be easy.

Chairman Mao, a chain smoker, once told his doctor that it was not an addiction but a “breathing exercise”. Deng Xiaoping – another heavy smoker – was seen fidgeting nervously during a 1986 lunch with the Queen, until he was told he could smoke.

“I’ve never seen a man light up more cheerfully than that,” Geoffrey Howe, the then foreign secretary, later recalled.

China’s masses also developed a taste for the cigarette. More than half of Chinese men are smokers, according to the World Health Organisation (WHO) while seven of the world’s top 10 cigarette brands are Chinese.

Around 740 million people are forced to breath in secondhand smoke, according to Xinhua, China’s official news agency, while the average age at which Chinese people start smoking is under 11.

China has repeatedly pledged to rein in smoking but cigarette production has surged with factories churning out 25 trillion cigarettes since 2003. If those were laid out tip-to-tip they would stretch 2.1bn km or 52,496 times around the world, state media claimed.

The consequences of so much smoking are dramatic. Every 30 seconds somebody dies in China as a result of tobacco use, according to the WHO.

While Beijing’s battle against industrial air pollution makes global headlines, studies suggest smoking is in some ways a far greater risk. Beijingers often wear smog-busting facemasks when levels of a tiny airborne particle called PM2.5 hit 200. But the PM2.5 level in a restaurant where just three people are smoking is three times that, Bernhard Schwartländer, the WHO’s representative in China, claimed this year. With five smokers in the restaurant, PM2.5 levels would climb to 1,200.

“We do need the ‘war on air pollution’. But we also need a ‘war on tobacco’,” the WHO said last week.

The latest phase of that war began on Monday morning as anti-smoking placards went up in bars, restaurants and once smoky basement clubs such as the Ding Junhui snooker hall.

Within hours of the ban starting, ashtrays had vanished from the club’s tables and staff had posted anti-smoking notices next to posters of snooker greats such as Steve Davis, Stephen Hendry and John Higgins.

One English-language warning, next to a photograph of Ken Doherty, the Irish snooker champion, read: “Don’t smok” sic.

Another, in Chinese, said: “We encourage our members to follow the no-smoking rules. We are sorry for any inconvenience it causes.”

Sun Jianlin, the club’s 22-year-old floor manager, said: “Before there would be lots of people smoking but it’s all changed now.”

Three soggy cigarette butts discarded in a dustbin in the men’s toilet suggested not everything had changed but otherwise the club appeared smoke-free.

Li Dongjing, a real estate developer who was playing on table 15, said he had anticipated the ban by swapping his smokes for a 1,200-yuan e-cigarette.

“I think smoking is bad. I wanted to change,” the 35-year-old said.

At Tongren hospital, Qi claimed he was winning his battle against errant smokers with nothing but politeness.

When he spotted someone smoking in an illegal area he told them: “Excuse me. The smoking ban kicks in today. You’d better not smoke here.

“They say: ‘OK’,” he said.

By Monday afternoon, Qi said he had persuaded 10 people to put out their cigarettes. But the hospital cleaner was losing his own battle against tobacco.

“I smoke the cheap ones, the ones that cost 7 to 10 yuan per pack,” he admitted, grinning to reveal nicotine-stained teeth. “It’s a habit. I can’t stop.”